mtd: move manufacturer to the common cfi.h header file

This patch moves the MANUFACTURER_ST and MANUFACTURER_INTEL to the
include/linux/mtd/cfi.h header file and renames them to CFI_MFR_ST and
CFI_MFR_INTEL. CFI_MFR_ST was already present there.

All references in drivers/mtd/chips/cfi_cmdset_0001.c are updated to reflect
this.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>