drm/radeon/r100: Handle unknown family in r100_cp_init_microcode()

With -Werror:

    In function ‘r100_cp_init_microcode’,
	inlined from ‘r100_cp_init’ at drivers/gpu/drm/radeon/r100.c:1136:7:
    include/linux/printk.h:465:44: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
      465 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
	  |                                            ^
    include/linux/printk.h:437:17: note: in definition of macro ‘printk_index_wrap’
      437 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
	  |                 ^~~~~~~
    include/linux/printk.h:508:9: note: in expansion of macro ‘printk’
      508 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
	  |         ^~~~~~
    drivers/gpu/drm/radeon/r100.c:1062:17: note: in expansion of macro ‘pr_err’
     1062 |                 pr_err("radeon_cp: Failed to load firmware \"%s\"\n", fw_name);
	  |                 ^~~~~~

Fix this by converting the if/else if/... construct into a proper
switch() statement with a default to handle the error case.

As a bonus, the generated code is ca. 100 bytes smaller (with gcc 11.4.0
targeting arm32).
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/r100.c

@@ -1016,45 +1016,65 @@ static int r100_cp_init_microcode(struct radeon_device *rdev)
 
 	DRM_DEBUG_KMS("\n");
 
-	if ((rdev->family == CHIP_R100) || (rdev->family == CHIP_RV100) ||
-	    (rdev->family == CHIP_RV200) || (rdev->family == CHIP_RS100) ||
-	    (rdev->family == CHIP_RS200)) {
+	switch (rdev->family) {
+	case CHIP_R100:
+	case CHIP_RV100:
+	case CHIP_RV200:
+	case CHIP_RS100:
+	case CHIP_RS200:
 		DRM_INFO("Loading R100 Microcode\n");
 		fw_name = FIRMWARE_R100;
-	} else if ((rdev->family == CHIP_R200) ||
-		   (rdev->family == CHIP_RV250) ||
-		   (rdev->family == CHIP_RV280) ||
-		   (rdev->family == CHIP_RS300)) {
+		break;
+
+	case CHIP_R200:
+	case CHIP_RV250:
+	case CHIP_RV280:
+	case CHIP_RS300:
 		DRM_INFO("Loading R200 Microcode\n");
 		fw_name = FIRMWARE_R200;
-	} else if ((rdev->family == CHIP_R300) ||
-		   (rdev->family == CHIP_R350) ||
-		   (rdev->family == CHIP_RV350) ||
-		   (rdev->family == CHIP_RV380) ||
-		   (rdev->family == CHIP_RS400) ||
-		   (rdev->family == CHIP_RS480)) {
+		break;
+
+	case CHIP_R300:
+	case CHIP_R350:
+	case CHIP_RV350:
+	case CHIP_RV380:
+	case CHIP_RS400:
+	case CHIP_RS480:
 		DRM_INFO("Loading R300 Microcode\n");
 		fw_name = FIRMWARE_R300;
-	} else if ((rdev->family == CHIP_R420) ||
-		   (rdev->family == CHIP_R423) ||
-		   (rdev->family == CHIP_RV410)) {
+		break;
+
+	case CHIP_R420:
+	case CHIP_R423:
+	case CHIP_RV410:
 		DRM_INFO("Loading R400 Microcode\n");
 		fw_name = FIRMWARE_R420;
-	} else if ((rdev->family == CHIP_RS690) ||
-		   (rdev->family == CHIP_RS740)) {
+		break;
+
+	case CHIP_RS690:
+	case CHIP_RS740:
 		DRM_INFO("Loading RS690/RS740 Microcode\n");
 		fw_name = FIRMWARE_RS690;
-	} else if (rdev->family == CHIP_RS600) {
+		break;
+
+	case CHIP_RS600:
 		DRM_INFO("Loading RS600 Microcode\n");
 		fw_name = FIRMWARE_RS600;
-	} else if ((rdev->family == CHIP_RV515) ||
-		   (rdev->family == CHIP_R520) ||
-		   (rdev->family == CHIP_RV530) ||
-		   (rdev->family == CHIP_R580) ||
-		   (rdev->family == CHIP_RV560) ||
-		   (rdev->family == CHIP_RV570)) {
+		break;
+
+	case CHIP_RV515:
+	case CHIP_R520:
+	case CHIP_RV530:
+	case CHIP_R580:
+	case CHIP_RV560:
+	case CHIP_RV570:
 		DRM_INFO("Loading R500 Microcode\n");
 		fw_name = FIRMWARE_R520;
+		break;
+
+	default:
+		DRM_ERROR("Unsupported Radeon family %u\n", rdev->family);
+		return -EINVAL;
 	}
 
 	err = request_firmware(&rdev->me_fw, fw_name, rdev->dev);