drm/amdgpu: purge ip_discovery headers

those two headers are not needed for ip discovery
Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Emily Deng <Emily.Deng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c

@@ -23,9 +23,7 @@
 
 #include "amdgpu.h"
 #include "amdgpu_discovery.h"
-#include "soc15_common.h"
 #include "soc15_hw_ip.h"
-#include "nbio/nbio_2_3_offset.h"
 #include "discovery.h"
 
 #define mmRCC_CONFIG_MEMSIZE	0xde3