defconfig: arm: msm: Enable MSM_PERFORMANCE flag for msm8937

In 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: Iaef2c7b432e707a2f8ad5f90914cd3c55d504629
Signed-off-by: Varun Garg <gargv@codeaurora.org>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>