Staging: rtl8188eu: Fix warning of unchecked sscanf return value.

This patch fixes the warning "unchecked sscanf return value" in file
rtw_mp.c. Zero is returned in case sscanf fails or if less than expected
items are read and assigned successfully. I have decided to return zero,
because in previous conditional statements zero was returned in case of
failure.

While at it, I have also fixed the warning of line over 80
characters.

Signed-off-by: Elena Oat <oat.elena@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>