ARM: BCM53016: MR32: convert to Broadcom iProc I2C Driver

replaces the bit-banged i2c-gpio provided i2c functionality
with the hardware in the SoC.

During review of the MR32, Florian Fainelli pointed out that the
SoC has a real I2C-controller. Furthermore, the connected pins
(SDA and SCL) would line up perfectly for use. Back then I couldn't
get it working though and I left it with i2c-gpio (which worked).

Now we know the reason: the interrupt was incorrectly specified.
(Hence, this patch depends on Florian Fainelli's
"ARM: dts: BCM5301X: Fix I2C controller interrupt" patch).

Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Matthew Hagan <mnhagan88@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>