Define SZ_512, SZ_256 and SZ_16 in asm-arm/sizes.h.
Remove the definitions from the at91*_devices.c files.

(Dependent on ARM patch #4370/2)
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>