staging: rtl8712: line over 80 characters.

Fix coding style issues, which solves checkpatch.pl warning:
"WARNING: line over 80 characters".

Signed-off-by: Bhagyashri Dighole <digholebhagyashri@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>