[ARM] 3237/1: PXA I2C driver updates

Patch from Richard Purdie

This patch adds a check to see if the pxa i2c interface is enabled
before allowing it to be used and resets it if found to be disabled.
This automatically restores the interface if the device has been
suspended and resumed without causing any suspend/resume call ordering
issues.

The patch also fixes a build warning and adds an appropriate module
licence (the module is gpl according to the header).

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>