vt6655: RFbSetPower fix missing rate RATE_12M

commit 40c8790b upstream.

When the driver sets this rate a power of zero value is set causing
data flow stoppage until another rate is tried.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[lizf: Backported to 3.4: adjust indentation]
Signed-off-by: Zefan Li <lizefan@huawei.com>

drivers/staging/vt6655/rf.c

@@ -1029,6 +1029,7 @@ unsigned char byPwrdBm = 0;
 		break;
     case RATE_6M:
     case RATE_9M:
+    case RATE_12M:
     case RATE_18M:
         byPwr = pDevice->abyOFDMPwrTbl[uCH];
         if (pDevice->byRFType == RF_UW2452) {