Remove centos 9 and rhel 8 block in grub2 pkg-map

In the grub2 element the grub2-efi-x64-modules package
is missing in the centos 9 section, this cause a failure
because grub2 cannot find the neccecary files when
installing the bootloader on EFI systems.

It seems grub2-efi-x64-modules was not included in release
9, this is likely why the block was added initially without
this package. Since it is now there, the Centos 9 specific
block is no longer needed.

Removing the rhel 8 block as well, as it is identical to the
family "redhat" block i.e it is redundant.

Closes-Bug: #1957169
Change-Id: Ia6b0ecf0cd15fb23c6740543940ee513a8602afe

diskimage_builder/elements/grub2/pkg-map

@@ -1,20 +1,4 @@
 {
-  "release": {
-    "rhel": {
-      "8": {
-        "signed_grub_efi": "efibootmgr grub2-efi-x64-modules grub2-efi-x64",
-        "signed_shim_efi": "shim",
-        "grub_bios": "grub2"
-      }
-    },
-    "centos": {
-      "9": {
-        "signed_grub_efi": "efibootmgr grub2-efi-x64",
-        "signed_shim_efi": "shim",
-        "grub_bios": "grub2"
-      }
-    }
-  },
   "family":{
     "debian":{
       "signed_grub_efi": "grub-efi-amd64-signed",

releasenotes/notes/add-grub2-efi-x64-modules-for-centos-9-74401ca5ec8201c7.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    An issue causing bootloader installation to fail on EFI system was fixed.
+    grub2 could not find the neccecary files, adding the grub2-efi-x64-modules
+    package to the pkg-map for centos-9 in the grub2 element fixes the issue.
+    See bug: `1957169 <https://bugs.launchpad.net/tripleo/+bug/1957169>`_.