atmel_spi: clean up SPIv1 quirk handling

Currently, we have a flag called "new_1" which is basically equivalent
to cpu_is_at91rm9200(). The latter is also called directly a few places.

Clean up this mess by introducing a atmel_spi_v2() function for
determining the controller version, and move all version dependent code
over to use it. This allows us to remove the new_1 flag.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>