staging: drop fpgaboot driver

The gs_fpgaboot driver is totally broken since 2014 and no one even
noticed the driver is not probing. Given the quality of the driver
and its current state it makes sense to drop it.

Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20220204190847.3809405-1-ztong0001@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>