ARM: shmobile: Fix R-Car Gen2 regulator quirk

The quirk code currently detects all compatible I2C chips with a shared
IRQ line on all I2C busses, adds them into a list, and registers a bus
notifier. For every chip for which the bus notifier triggers, the quirk
code performs I2C transfer on that I2C bus for all addresses in the list.
The problem is that this may generate transfers to non-existing chips on
systems with multiple I2C busses.

This patch adds a check to verify that the I2C bus to which the chip with
shared IRQ is attached to matches the I2C bus of the chip which triggered
the bus notifier and only starts the I2C transfer if they match.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Tested-by: Nguyen Viet Dung <dung.nguyen.aj@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>