drm/i915/dg1: Update DMC_DEBUG register

Update the DMC_DEBUG_DC5 register to its new location and do not try
reading the DC6 counter since DG1 doesn't support DC6.

v2: Use IS_DGFX() instead of IS_DG1(). Even if not having DC6 is not
directly related to DGFX, the register move to a new location is. So in
future, if there is one supporting DC6, it would just need to add the
other register rather than fixing the case of a wrong register being
read (Matt)

Cc: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201014191937.1266226-10-lucas.demarchi@intel.com

drivers/gpu/drm/i915/display/intel_display_debugfs.c

@@ -518,8 +518,13 @@ static int i915_dmc_info(struct seq_file *m, void *unused)
 		   CSR_VERSION_MINOR(csr->version));
 
 	if (INTEL_GEN(dev_priv) >= 12) {
+		if (IS_DGFX(dev_priv)) {
+			dc5_reg = DG1_DMC_DEBUG_DC5_COUNT;
+		} else {
 			dc5_reg = TGL_DMC_DEBUG_DC5_COUNT;
 			dc6_reg = TGL_DMC_DEBUG_DC6_COUNT;
+		}
+
 		/*
 		 * NOTE: DMC_DEBUG3 is a general purpose reg.
 		 * According to B.Specs:49196 DMC f/w reuses DC5/6 counter

drivers/gpu/drm/i915/i915_reg.h

@@ -7536,6 +7536,7 @@ enum {
 #define BXT_CSR_DC3_DC5_COUNT	_MMIO(0x80038)
 #define TGL_DMC_DEBUG_DC5_COUNT	_MMIO(0x101084)
 #define TGL_DMC_DEBUG_DC6_COUNT	_MMIO(0x101088)
+#define DG1_DMC_DEBUG_DC5_COUNT	_MMIO(0x134154)
 
 #define DMC_DEBUG3		_MMIO(0x101090)