efi: translate errno to EFI status on exit

Translate the given errno to an efi status instead of always exiting
with EFI_LOAD_ERROR.

stand/efi/boot1/boot1.c

@@ -299,9 +299,9 @@ efi_exit(EFI_STATUS s)
 }
 
 void
-exit(int error __unused)
+exit(int error)
 {
-	efi_exit(EFI_LOAD_ERROR);
+	efi_exit(errno_to_efi_status(error));
 }
 
 /*

stand/efi/loader/efi_main.c

@@ -49,7 +49,7 @@ void
 exit(int status)
 {
 
-	efi_exit(EFI_LOAD_ERROR);
+	efi_exit(errno_to_efi_status(status));
 }
 
 static CHAR16 *