media: pvrusb2: fix the retry logic

As reported by this warning:
	drivers/media/usb/pvrusb2/pvrusb2-encoder.c:263 pvr2_encoder_cmd() warn: continue to end of do { ... } while(0); loop

There's an issue at the retry logic there: the current logic is:

	do {
		if (need_to_retry)
			continue;

		some_code();
	} while (0);

Well, that won't work, as continue will make it test for zero, and
abort the loop. So, change the loop to:

	while (1) {
		if (need_to_retry)
			continue;

		some_code();
		break;
	};

With seems to be what's actually expected there.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/pvrusb2/pvrusb2-encoder.c

@@ -198,7 +198,7 @@ static int pvr2_encoder_cmd(void *ctxt,
 	}
 
 
-	LOCK_TAKE(hdw->ctl_lock); do {
+	LOCK_TAKE(hdw->ctl_lock); while (1) {
 
 		if (!hdw->state_encoder_ok) {
 			ret = -EIO;
@@ -293,9 +293,9 @@ rdData[0]);
 
 		wrData[0] = 0x0;
 		ret = pvr2_encoder_write_words(hdw,MBOX_BASE,wrData,1);
-		if (ret) break;
+		break;
 
-	} while(0); LOCK_GIVE(hdw->ctl_lock);
+	}; LOCK_GIVE(hdw->ctl_lock);
 
 	return ret;
 }