efi_loader: fix SectionAlignment, FileAlignment

efi_loader: fix SectionAlignment, FileAlignment

The alignment of sections in the EFI binaries generated by U-Boot is
incorrect.

According to the PE-COFF specification [1] the minimum value for
FileAlignment is 512. If the value of SectionAlignment is
less then the page size, it must equal FileAlignment.

Let's set both values to 512 for the ARM and RISC-V architectures.

[1] https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>