ARM: dts: msm: Fix ap2mdm_pon_reset configuration for SM8150+SDX50

MDM PON control should not be driven low except when set by esoc.
Remove output-low property to meet this requirement.

Change-Id: Iae7742e51b46e633846212a2dcc10a9cf47875a2
Signed-off-by: Adam Bickett <abickett@codeaurora.org>