wireless: add plfxlc driver for pureLiFi X, XL, XC devices

This is a driver for pureLiFi X, XL, XC devices which use light to transmit
data, so they are not compatible with normal Wi-Fi devices. The driver uses
separate NL80211_BAND_LC band to distinguish from Wi-Fi.  The driver is based
on 802.11 softMAC Architecture and uses native 802.11 for configuration and
management. Station and Ad-Hoc modes are supported.

The driver is compiled and tested in ARM, x86 architectures and compiled in
powerpc architecture. This driver implementation has been based on the zd1211rw
driver.

Signed-off-by: Srinivasan Raju <srini.raju@purelifi.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220224182042.132466-3-srini.raju@purelifi.com