defconfig: arm: msm: Disable MSM_PERFORMANCE_HOTPLUG_ON flag

In msm8937_defconfig and msm8937-perf_defconfig config files
MSM_PERFORMANCE_HOTPLUG_ON flags is not required, as core
control module performs the cpus hotplug operations.
MSM_PERFORMANCE_HOTPLUG_ON flag is getting enabled when
MSM_PERFORMANCE flag enabled, so disable
MSM_PERFORMANCE_HOTPLUG_ON config flag for msm8937 target.

Change-Id: Iba68b570c169e4d0c723f23a92c1fd2e03ad7495
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>