staging: r8188eu: Simplify code concerning SupportPlatform

This member of struct odm_dm_struct is always set to ODM_CE in this driver.
As a result, a number of switch and if statements can be simplified. In
addition, a number of routines are no longer used and can be removed.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>