staging: rtl8192u: Refactor heavy nesting

This patch fixes warnings raised by checkpatch.pl relating to heavily indented
lines in r8192U_dm.c by refactoring code to achieve the same outcome indented by
one less tab.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>