at91_cf, minor fix

This is a minor correctness fix: since the at91_cf driver probe() routine
is in the init section, it should use platform_driver_probe() instead of
leaving that pointer around in the driver struct after init section
removal.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>