drm/amd: fix compiler error to support older compilers

‘for’ loop initial declarations are only allowed in C99 or C11 mode
Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Reviewed-by: Mukul Joshi <mukul.joshi@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -360,7 +360,7 @@ static int aqua_vanjaram_xcp_mgr_init(struct amdgpu_device *adev)
 
 int aqua_vanjaram_init_soc_config(struct amdgpu_device *adev)
 {
-	u32 inst_mask = adev->sdma.sdma_mask;
+	u32 mask, inst_mask = adev->sdma.sdma_mask;
 	int ret, i, num_inst;
 
 	/* generally 1 AID supports 4 instances */
@@ -370,7 +370,7 @@ int aqua_vanjaram_init_soc_config(struct amdgpu_device *adev)
 	adev->aid_mask = i = 1;
 	inst_mask >>= adev->sdma.num_inst_per_aid;
 
-	for (const u32 mask = (1 << adev->sdma.num_inst_per_aid) - 1; inst_mask;
+	for (mask = (1 << adev->sdma.num_inst_per_aid) - 1; inst_mask;
 	     inst_mask >>= adev->sdma.num_inst_per_aid, ++i) {
 		if ((inst_mask & mask) == mask)
 			adev->aid_mask |= (1 << i);