drivers:misc: ti-st: remove multiple gpio handling

TI shared transport driver previously intended to expose rfkill
entries for each of the protocol gpio that the chip would have.
However now in case such gpios exist, which requires to be enabled
for a specific protocol, the responsibility lay on protocol driver.
This patch removes the request/free of multiple gpios, rfkill struct
references and also removes the chip_toggle function.

Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>