msm: Add necessary support to build fsm9900 target

Add the Kconfig and Makefile entries needed to support
the FSM9900 target

Change-Id: I3f995df7357640d3679b6c14e609e9a529fc508a
Acked-by: Kaushik Sikdar <ksikdar@qti.qualcomm.com>
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>