drm: Copy back ioctl data to userspace regardless of return code.

Fixes a regression from commit 9d5b3ffc42f7820e8ee07705496955e4c2c38dd9
('drm: fixup some of the ioctl function exit paths'): The vblank ioctl
needs to update the userspace parameters when interrupted by a signal,
which was prevented by the return code check. This could cause the X
server to hang in drmWaitVBlank().

Signed-off-by: Michel Dänzer <[e-mail]>
Signed-off-by: Jesse Barnes <[e-mail]>

drivers/gpu/drm/drm_drv.c

···
 		}
 		retcode = func(dev, kdata, file_priv);
 
-		if ((retcode == 0) && (cmd & IOC_OUT)) {
+		if (cmd & IOC_OUT) {
 			if (copy_to_user((void __user *)arg, kdata,
 					 _IOC_SIZE(cmd)) != 0)
 				retcode = -EFAULT;