Bluetooth: Silence warning in btmrvl SDIO driver

Clone checking of ret to simplify the code.

This patch silences a compiler warning:
drivers/bluetooth/btmrvl_sdio.c: In function ‘btmrvl_sdio_verify_fw_download’:
drivers/bluetooth/btmrvl_sdio.c:80: warning: ‘fws1’ may be used uninitialized in this function
drivers/bluetooth/btmrvl_sdio.c:80: note: ‘fws1’ was declared here

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Reviewed-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>