fbcon: use kvmalloc() for scrollback buffer

Scrollback frame buffer is rather big - 32K,
so it requires 3rd order page, so let's use kvmalloc() instead of
ordinary kmalloc() for it.
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/core/fbcon.c

@@ -999,7 +999,7 @@ static const char *fbcon_startup(void)
 			if (!softback_buf) {
 				softback_buf =
 				    (unsigned long)
-				    kmalloc(fbcon_softback_size,
+				    kvmalloc(fbcon_softback_size,
 					    GFP_KERNEL);
 				if (!softback_buf) {
 					fbcon_softback_size = 0;
@@ -1008,7 +1008,7 @@ static const char *fbcon_startup(void)
 			}
 		} else {
 			if (softback_buf) {
-				kfree((void *) softback_buf);
+				kvfree((void *) softback_buf);
 				softback_buf = 0;
 				softback_top = 0;
 			}
@@ -3672,7 +3672,7 @@ static void fbcon_exit(void)
 	}
 #endif
 
-	kfree((void *)softback_buf);
+	kvfree((void *)softback_buf);
 	softback_buf = 0UL;
 
 	for_each_registered_fb(i) {