[U-Boot] [U-Boot, v2, 3/6] x86: efi: app: Generate Microsoft PE format compliant image

[Alexander Graf]

> Per Microsoft PE Format documentation [1], PointerToSymbolTable and
> NumberOfSymbols should be zero for an image in the COFF file header.
> Currently U-Boot is generating u-boot-app.efi in which these two
> members are not zero.
> 
> This updates the build rules to tell linker to remove the symbol
> table completely 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 at gmail.com>
> Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

Thanks, applied to efi-next

Alex