msm: mdm2: Add delay between subsequent PS_HOLD

During SSR first a reset of external modem is issued
and mdm_do_soft_power_on() toggles ap2mdm_soft_reset which
in turn toogles the PS_HOLD. Then a part of SSR external
modem is powered up and mdm_do_soft_power_on() again toggles
the gpio. For PMIC register stabilization we need a 1sec delay
between subsequent mdm_do_soft_power_on().
By default the delay is 500msec, so adding another 500msec for
stablization.

Change-Id: I928c064f386c1e376fc5b0740c2d1336f549398f
Signed-off-by: Taniya Das <tdas@codeaurora.org>