misc: mic: scif: remove redundant check on ret < 0

misc: mic: scif: remove redundant check on ret < 0

The check for ret < 0 is redundant as any places prior to this point
where ret is set to an error value the code will exit out of the loop
to the error exit label 'err'.  Remove this redundant dead code.

Detected by CoverityScan, CID#1339528 ("Logically dead code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>