usb: phy msm: Do msm_otg_notify_chg_current in sleepable context

The charger driver's implementation of power_supply_set_property() for
POWER_SUPPLY_CURRENT_MAX currently uses a mutex. Since
sleeping is disallowed in this case, instead schedule a
work function to do the call.

Change-Id: Icad8be033dd0782c155ac8858a15580844415ba4
Signed-off-by: Sundara Vinayagam <sundvi@codeaurora.org>