In preparation of creating a standalone MM version of the NOR Flash driver, refactor the existing pieces into a core driver. NorFlashDxe.c has the DXE instantiation code, FVB initialization code and some common functions. Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>