ipw2100: remove strange symbol prefixes

From: Pavel Machek <pavel@ucw.cz>

ipw2100 uses strange X__ prefixes even for symbols already prefixed
by ipw2100. Fixed.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jiri Benc <jbenc@suse.cz>