Staging: rtl8188eu: Refactored code to increase readility

Refactored the conditional code to make it more compact.
Replaced the ternary operators with abs() macro to increase readability.

Signed-off-by: Vatika Harlalka <vatikaharlalka@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>