[I2C] pxa: provide late suspend and early resume hooks

Properly hook the I2C driver into the PM code; the previous fix for
this (ece5f7b3c4fde70a1ae4add7372ebca5c90bc34d) worked around the
platform where I2C is required to be available early during resume.

It has been found to be sufficient to use the early resume hook for
this function, so the original hack can die.  Leave the hack in
place for the PIO transfer handler though.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>