serial: max3107: introduce a max3107 driver

This device is used by some of the Intel MID platforms. It's not similar
enough to the MAX3100 to use the same driver.

At this point the driver is specific to the platform and not generalised.
We will fix that later.

Signed-off-by: jianwei.yang <jianwei.yang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>