efi: Drop all uses of efi_call_XX() wrappers

efi: Drop all uses of efi_call_XX() wrappers

Now that GCC can generate function calls using the correct calling
convention for us, we can stop using the efi_call_XX() wrappers, and
just dereference the function pointers directly.

This avoids the untyped variadic wrapper routines, which means better
type checking for the method calls.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>