[ARM] 3950/1: AT91: Split up system header file

The AT91RM9200 system header file (at91rm9200_sys.h) has been split into
separate header files for each peripheral.  This was necessary since
some of the system peripherals are also used on AT91SAM9260 and
AT91SAM9261.

The new SAM9-specific register bits have also been defined.

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