Input: lm8323 - remove driver

The LM8323 keypad driver relies exclusively on legacy platform data,
has no Device Tree or generic device property support, and has no users
in mainline (including the Nokia N810 DTS, which never added support
for it). Its PWM/LED handling and unbind lifetime are broken, and after
hardware-tested IRQ fixes in 2011 the driver has for over a decade only
received mechanical API conversions and static-analysis cleanups
without hardware testing.

An inquiry on the mailing list asking whether anyone still uses or
wishes to keep the driver received no objections. Remove the driver
and its platform data header.

Link: https://lore.kernel.org/r/Zr6I9RB5mibU_12N@google.com
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20261109072950.3474308-2-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>