drm/amdgpu: Add H/W agnostic amdgpu <--> amdkfd interface

This patch adds an interface file between amdgpu and amdkfd. This
interface file is H/W agnostic, thus containing functions that
operate the same for any AMD APU/GPU H/W generation.

The functions in this interface mirror (some) of the functions in
radeon_kfd.c (the radeon<-->amdkfd interface file). The main functions
are:

- amdgpu_amdkfd_init - initialize the amdkfd module
- amdgpu_amdkfd_load_interface - load the H/W interface according to the
  currently probed device
- amdgpu_amdkfd_device_probe - probe the device in amdkfd
- amdgpu_amdkfd_device_init - initialize the device in amdkfd
- amdgpu_amdkfd_interrupt - call the ISR of amdkfd
- amdgpu_amdkfd_suspend - suspend callback from amdgpu
- amdgpu_amdkfd_resume - resume callback from amdgpu

This patch also modifies the relevant amdgpu files, to use this new
interface.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/cik.c b/drivers/gpu/drm/amd/amdgpu/cik.c
index 341c566..b3b66a0 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik.c
@@ -64,6 +64,8 @@
 #include "oss/oss_2_0_d.h"
 #include "oss/oss_2_0_sh_mask.h"
 
+#include "amdgpu_amdkfd.h"
+
 /*
  * Indirect registers accessor
  */
@@ -2448,14 +2450,21 @@
 {
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 
+	amdgpu_amdkfd_suspend(adev);
+
 	return cik_common_hw_fini(adev);
 }
 
 static int cik_common_resume(void *handle)
 {
+	int r;
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 
-	return cik_common_hw_init(adev);
+	r = cik_common_hw_init(adev);
+	if (r)
+		return r;
+
+	return amdgpu_amdkfd_resume(adev);
 }
 
 static bool cik_common_is_idle(void *handle)