msm: fsm9900: Add support for GSM NL HW module

Add support to enable the serial UART port on DIQ connector to
control the GSM NL module. This feature is enabled by default in
fsm9900 targets.

Change-Id: Ief50c896468999121efee882285d16de2da5684f
Acked-by: Jie Luo <jluo@qti.qualcomm.com>
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>