msm: defconfig: Enable CONFIG_CPUIDLE_MULTIPLE_DRIVERS

MSM8939 device has cpus with different latencies. Enable above
mentioned config to allow the cpuidle framework to use different
drivers for different CPUs.

Change-Id: If003fd9cd86276753d8cfa5cabaeb2c1c87c44c5
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>