drm/amdgpu: Use less generic enum definitions

alpha:allmodconfig fails to build as follows.

drivers/gpu/drm/amd/amdgpu/amdgpu.h:1006:2: error:
	expected identifier before '(' token
drivers/gpu/drm/amd/amdgpu/amdgpu.h:1011:28: error:
	'NGG_BUF_MAX' undeclared here

The problem is not really the enum definition of NGG_BUF_MAX but PARAM,
which happens to be defined differently for alpha and a couple of other
architectures.

Use less generic defines for NGG enums to solve the problem.

Fixes: bce23e00f3369 ("drm/amdgpu: add NGG parameters")
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 8033001..86923c5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1004,10 +1004,10 @@ struct amdgpu_ngg_buf {
 };
 
 enum {
-	PRIM = 0,
-	POS,
-	CNTL,
-	PARAM,
+	NGG_PRIM = 0,
+	NGG_POS,
+	NGG_CNTL,
+	NGG_PARAM,
 	NGG_BUF_MAX
 };