ARM: dts: msm: remove VDD_MMCX always-on configuration for Kona

Remove the always-on flag for VDD_MMCX which was originally added as a
workaround to keep the system from crashing as a result of erroneous
accesses to the display clock driver. The unintended access occured
due to an attempt from the clock framework to parent an orphaned display
clock during the probe of an audio clock driver.

Change-Id: Ifed4aa8df8c887a87f9f2c83076334afdf910925
Signed-off-by: David Dai <daidavid1@codeaurora.org>