pxa2xx_spi: minor cleanup

Minor fixes: remove redundant local variable initialization, fix "can not"
to what I _think_ is a preferred spelling, output IRQ number if requesting
it failed.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
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>