Staging: rtl8192su: all rtl8192su chips have the 93c46 eprom

all rtl8192su chips have the 93c46 eprom. (no 93c56)
it it theoretically safe to remove the 93c56 definitions and some unneeded code.
if your device stops working after this patch, please send me a mail
and include some information about your device:
* dmesg
* lsusb -v
* _exact_ chipset (version)
* vendor
* everything else, that may help

plus cosmetics.

Signed-off-by: Florian Schilhabel <florian.c.schilhabel@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>