grub: Fix insane/QA architecture warning

There is QA warning about this package for an architecture mismatch but this is inappropriate in this case since the bootloader needs 32 and 64 bit code. We therefore flag the QA check to be skipped.

---

index b910b5a..ba41e8f 100644
@@ -41,4 +41,4 @@ do_install_append () {
 
 FILES_${PN}-doc = "${datadir}"
 FILES_${PN} = "/usr /etc"
-
+INSANE_SKIP_${PN} = "arch"