drm/radeon/si: Fix inconsistent indenting

Kernel test robot throws below warning ->

smatch warnings:
drivers/gpu/drm/radeon/si.c:4514 si_vm_packet3_cp_dma_check() warn:
inconsistent indenting

Fixed the inconsistent indenting.
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NYang Li <yang.lee@linux.alibaba.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/si.c

@@ -4511,7 +4511,7 @@ static int si_vm_packet3_cp_dma_check(u32 *ib, u32 idx)
 			} else {
 				for (i = 0; i < (command & 0x1fffff); i++) {
 					reg = start_reg + (4 * i);
-				if (!si_vm_reg_valid(reg)) {
+					if (!si_vm_reg_valid(reg)) {
 						DRM_ERROR("CP DMA Bad DST register\n");
 						return -EINVAL;
 					}