Staging: cx25821: Delete file cx25821-gpio.h

Delete file cx25821-gpio.h since it is not used.

Signed-off-by: Leonid V. Fedorenchik <leonidsbox@gmail.com>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reviewed-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>