mtd_dataflash: fix probing of AT45DB321C chips.

Commit 771999b6 ("[MTD] DataFlash: bugfix,
binary page sizes now handled") broke support for probing AT45DB321C flash
chips.  These chips do not support the "page size" status bit, so if we
match the JEDEC id return early.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Will Newton <will.newton@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>