drivers/misc/ti-st: check chip_awake NULL check

Before calling on any of the platform hooks, shared transport driver checks
for the validity of the platform hooks as to whether it is provided or not.
A wrong function was being checked for, before the chip_awake hook was called
by the HCI-LL sleep logic handler. This patch corrects the check.

Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>