Drop use of drmP.h in all files named amdgpu*
in drm/amd/amdgpu/

Fix fallout.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190609220757.10862-10-sam@ravnborg.org

We get a few warnings when building kernel with W=1:
drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c:113:6: warning: no previous prototype for 'amdgpu_pll_compute' [-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/cz_smc.c:38:10: warning: no previous prototype for 'cz_get_argument' [-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/cz_smc.c:302:5: warning: no previous prototype for 'cz_smu_start' [-Wmissing-prototypes]
....

In fact, these functions are declared in
drivers/gpu/drm/amd/amdgpu/atombios_i2c.h
drivers/gpu/drm/amd/amdgpu/amdgpu_pll.h
drivers/gpu/drm/amd/amdgpu/cz_dpm.h
drivers/gpu/drm/amd/amdgpu/vi_dpm.h.
So this patch adds missing header dependencies.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

This adds the non-asic specific core driver code.

v2: remove extra kconfig option
v3: implement minor fixes from Fengguang Wu
v4: fix cast in amdgpu_ucode.c

Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jammy Zhou <Jammy.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>