Input: iqs7222 - remove support for RF filter

The vendor has marked the RF filter enable control as reserved in
the datasheet; remove it from the driver.

Fixes: e505edae ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Link: https://lore.kernel.org/r/20220626072412.475211-7-jeff@labundy.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>