[ARM] 3592/1: AT91RM9200 Serial driver update

Patch from Andrew Victor

This patch includes a number of updates to the AT91RM9200 serial driver.

Changes include:
1. Conversion to a platform_driver.  [Ivan Kokshaysky]
2. Replaced all references to AT91RM9200 with AT91.  This driver can now
also be used for the AT91SAM9216.
3. Allow TIOCM_LOOP to configure local loopback mode.
4. Cleaned up the 'read_status_mask' usage and interrupt handler code.
[Chip Coldwell]
5. Suspend/resume support.  [David Brownell]

There are a few 'unused variable' warning when compiling this - I
removed the new DMA support to keep this first patch simpler.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>