defconfig: msmfalcon: enable compilation of MDSS PLL driver

Add necessary configuration to enable compilation of MDSS
PLL driver which is now based on common clock framework for
msmfalcon platform.

Change-Id: Iba01736475b852d8d64f944c371e585c94b85114
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>