rtl8180 has one register for analog converters setting ,rtl8185 has
two and rtl8187se has three.
Setting those registers require more than a simple write, and for
one of them a function is already provided.
This patch introduces functions for the other two.
rtl8187se will use them. rtl8185 doesen't yet, but should
Signed-off-by: NAndrea Merello <andrea.merello@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>