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>

grub-core/lib/efi/halt.c

@@ -34,8 +34,8 @@ grub_halt (void)
     !defined(__loongarch__) && !defined(__riscv)
   grub_acpi_halt ();
 #endif
-  efi_call_4 (grub_efi_system_table->runtime_services->reset_system,
-              GRUB_EFI_RESET_SHUTDOWN, GRUB_EFI_SUCCESS, 0, NULL);
+  grub_efi_system_table->runtime_services->reset_system (GRUB_EFI_RESET_SHUTDOWN,
+							 GRUB_EFI_SUCCESS, 0, NULL);
 
   while (1);
 }