power: supply: qti_battery_charger: update USB power supply type runtime

Currently, USB power supply type is set to POWER_SUPPLY_TYPE_USB
in power supply descriptor. power_supply_show_property() would
show POWER_SUPPLY_PROP_TYPE based on psy->desc->type. Userspace
process like healthd would read POWER_SUPPLY_PROP_TYPE to print
the adapter type in logs (e.g. "chg=u" for SDP, "chg=a" for DCP).
Hence update usb_psy_desc type runtime to show the USB power
supply type accordingly. This is useful for testing.

Change-Id: Icd88098f97beba053105d826614b4182f3716144
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>