drm/xe: Remove dependency on intel_mchbar_regs.h

The only thing really needed is the base offset, MCHBAR_MIRROR_BASE_SNB.
Remove the include and just define it inplace.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_guc_pc.c

@@ -21,9 +21,9 @@
 #include "xe_mmio.h"
 #include "xe_pcode.h"
 
-#include "intel_mchbar_regs.h"
+#define MCHBAR_MIRROR_BASE_SNB	0x140000
 
-/* For GEN6_RP_STATE_CAP.reg to be merged when the definition moves to Xe */
+#define GEN6_RP_STATE_CAP			_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5998)
 #define   RP0_MASK				REG_GENMASK(7, 0)
 #define   RP1_MASK				REG_GENMASK(15, 8)
 #define   RPN_MASK				REG_GENMASK(23, 16)