[U-Boot] [U-Boot, 3/4] efi_loader: add checking for incorrect use of EFI_ENTRY/EXIT

[Alexander Graf]

> Missing an EFI_ENTRY() or doubling up EFI_EXIT() leads to non-obvious
> crashes.  Let's add some error checking.
> 
> Signed-off-by: Rob Clark <robdclark at gmail.com>

Thanks, applied to efi-next

Alex