staging: rtl8192e: rtllib: fix macro style issue

Remove macro and use explicit case statements. Code is a little
longer but clearer. Checkpatch.pl does not complain anymore.

Signed-off-by: Ioan-Adrian Ratiu <adi@adirat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>