drm/amd/amdgpu: Fix asm/hypervisor.h build error.

Add CONFIG_X86 check to fix the build error.

Fixes: 49aa98ca30cd18 ("drm/amd/amdgpu: Only reserve vram for firmware with vega9 MS_HYPERV host.")
Reported-by: kernel test robot <[e-mail]>
Signed-off-by: Yongqiang Sun <[e-mail]>
Acked-by: Alex Deucher <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
  */
 
 #include <linux/io-64-nonatomic-lo-hi.h>
+#ifdef CONFIG_X86
 #include <asm/hypervisor.h>
+#endif
 
 #include "amdgpu.h"
 #include "amdgpu_gmc.h"
···
 		/*
 		 * VEGA10 SRIOV VF with MS_HYPERV host needs some firmware reserved area.
 		 */
+#ifdef CONFIG_X86
 		if (amdgpu_sriov_vf(adev) && hypervisor_is_type(X86_HYPER_MS_HYPERV)) {
 			adev->mman.stolen_reserved_offset = 0x500000;
 			adev->mman.stolen_reserved_size = 0x200000;
 		}
+#endif
 		break;
 	case CHIP_RAVEN:
 	case CHIP_RENOIR: