arm: efi: Generate Microsoft PE format compliant images

Per Microsoft PE Format documentation [1], PointerToSymbolTable and
NumberOfSymbols should be zero for an image in the COFF file header.
Currently the COFF file header is hardcoded on ARM and these two
members are not zero.

This updates the hardcoded structure to clear these two members, as
well as setting the flag IMAGE_FILE_LOCAL_SYMS_STRIPPED so that we
can generate compliant *.efi images.

[1] https://docs.microsoft.com/zh-cn/windows/desktop/Debug/pe-format



Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>