Staging: rtlwifi: halmac: Remove unnecessary 'out of memory' messages

Remove unnecessary messages because OOM (Out Of Memory Manager)
reports memory allocation fail messages. The return value
is clear regarding the problem, so there is no need for the
'out of memory' comments. Also, delete braces {} for single
if statement blocks to improve the coding style.

Fix issues found by by checkpatch.pl.
WARNING: Possible unnecessary 'out of memory' message.
WARNING: braces {} are not necessary for single statement blocks

Signed-off-by: Georgiana Chelu <georgiana.chelu93@example.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>