[ARM] 4752/1: [AT91] RTT, RTC and WDT peripherals on SAM9

Add platform_device and initialization for the RTT (Real Time Timer)
and WDT (Watchdog) integrated in the Atmel AT91SAM9 processors.

For SAM9263, register both RTT peripherals.
   [From: David Brownell <dbrownell@users.sourceforge.net>]

Provide platform_resources for RTT peripherals
  [From: David Brownell <dbrownell@users.sourceforge.net>]

Add support for RTC peripheral on AT91SAM9RL (same RTC peripherals as
AT91RM9200)
  [From: David Brownell <dbrownell@users.sourceforge.net>]

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