drm/amd/display: Don't build DCN1 when kcov is enabled

DCN1 contains code that utilizes fp math. When
CONFIG_KCOV_INSTRUMENT_ALL and CONFIG_KCOV_ENABLE_COMPARISONS are
enabled, build errors are found. See this earlier patch for details:

https://lists.freedesktop.org/archives/dri-devel/2018-August/186131.html

As a short term solution, disable CONFIG_DRM_AMD_DC_DCN1_0 when
KCOV_INSTRUMENT_ALL and KCOV_ENABLE_COMPARISONS are enabled. In
addition, make it a fully derived config, taking into account
CONFIG_X86.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/Kconfig

@@ -4,18 +4,16 @@ menu "Display Engine Configuration"
 config DRM_AMD_DC
 	bool "AMD DC - Enable new display engine"
 	default y
+	select DRM_AMD_DC_DCN1_0 if X86 && !(KCOV_INSTRUMENT_ALL && KCOV_ENABLE_COMPARISONS)
 	help
 	  Choose this option if you want to use the new display engine
 	  support for AMDGPU. This adds required support for Vega and
 	  Raven ASICs.
 
 config DRM_AMD_DC_DCN1_0
-	bool "DCN 1.0 Raven family"
-	depends on DRM_AMD_DC && X86
-	default y
+	def_bool n
 	help
-	  Choose this option if you want to have
-	  RV family for display engine
+	  RV family support for display engine
 
 config DEBUG_KERNEL_DC
 	bool "Enable kgdb break in DC"