mtd: cfi_cmdset_0002: add 0xFF intolerance for M29W128G

The M29W128G Numonyx flash devices are intolerant to any 0xFF command:
in the Cfi_util.c the function cfi_qry_mode_off() (that resets the device
after the autoselect mode) must have a 0xF0 command after the 0xFF command.
This fix solves also the cause of the fixup_M29W128G_write_buffer() fix,
that can be removed now.
The following patch applies to 2.6.30 kernel.

Signed-off-by: Massimo Cirillo <maxcir@gmail.com>
Acked-by: Alexey Korolev <akorolev@infradead.org>
Cc: stable@kernel.org
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>