staging: brcm80211: made fullmac error codes more consistent

Code cleanup. The code contains several checks on the condition
SDIOH_API_SUCCESS(status). On failure, the error returned depended on the
check, instead of being consistent. This has been corrected.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>