[PATCH] at91_serial -> atmel_serial: Kconfig symbols

Rename the following Kconfig symbols:
  * CONFIG_SERIAL_AT91 -> CONFIG_SERIAL_ATMEL
  * CONFIG_SERIAL_AT91_CONSOLE -> CONFIG_SERIAL_ATMEL_CONSOLE
  * CONFIG_SERIAL_AT91_TTYAT -> CONFIG_SERIAL_ATMEL_TTYAT

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>