drm/amdgpu: Support new arcturus mtype

Arcturus repurposed mtype WC to RW. Modify gmc functions
to support the new mtype

Signed-off-by: Oak Zeng <[e-mail]>
Signed-off-by: Felix Kuehling <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Reviewed-by: Shaoyun Liu <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

···
 	case AMDGPU_VM_MTYPE_WC:
 		pte_flag |= AMDGPU_PTE_MTYPE_VG10(MTYPE_WC);
 		break;
+	case AMDGPU_VM_MTYPE_RW:
+		pte_flag |= AMDGPU_PTE_MTYPE_VG10(MTYPE_RW);
+		break;
 	case AMDGPU_VM_MTYPE_CC:
 		pte_flag |= AMDGPU_PTE_MTYPE_VG10(MTYPE_CC);
 		break;

drivers/gpu/drm/amd/include/vega10_enum.h

···
 typedef enum MTYPE {
 MTYPE_NC                                 = 0x00000000,
 MTYPE_WC                                 = 0x00000001,
+MTYPE_RW                                 = 0x00000001,
 MTYPE_CC                                 = 0x00000002,
 MTYPE_UC                                 = 0x00000003,
 } MTYPE;