rtl8187: Remove module warning and dependence on CONFIG_EXPERIMENTAL

After considerable testing, the initial fears that the driver might damage
some flavors of RTL8187B hardware seem to be groundless. Accordingly, the
logged warning is removed. In addition, Kconfig is changed to remove the
dependence on EXPERIMENTAL.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger>
Acked-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>