Staging: rtl8188eu: include: Remove unnecessary macro

This patch removes a macro which is not used anywhere except in the header
file. The existing usage in the header file is replaced with the actual value.

Signed-off-by: Mahati Chamarthy <mahati.chamarthy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>