power: smb1351-charger: stay awake during i2c transactions

I2C transactions can timeout if the bus is already suspended
when the I2C transaction is initiated. Prevent this by holding
the device wake during I2C transactions.

Note that if the transaction is initiated after suspend_noirq,
the transaction will still timeout, but the I2C retry will
ensure the transaction goes through.

Change-Id: Ic9ff3f5372ff774715256ea3cc6da7496c75031f
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>