power: supply: qti_battery_charger: Change wireless power supply type

Now that the power supply framework has POWER_SUPPLY_TYPE_WIRELESS
change the wireless power supply type from MAINS to WIRELESS. This
would help android healthd to show "chg=w" rather than "chg=a" in
logs when a wireless charger is connected.

Change-Id: I871779aa806f775e2cdf1e0994593fc991fe77f9
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>