[Bug 2098641] [NEW] grub 2.06 prob fat fs fail.

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I found this issue on Ubuntu 22.04.5 LTS, but it's a general issue for grub-2.06.
This is my setup information：
      nvme0n1
      ├─nvme0n1p1  vfat   FAT32 EFI0  5282-D345                              40.6M    17% /boot/efi
      └─nvme0n1p2  ext4   1.0   OS0   bdfcdb95-b1c7-42ea-b1b8-69c20099586e  105.6G     4% /
The first partition is /dev/nvme0n1p1, FAT format.
The grub prefix environment value default be set:
      prefix=(hd0,gpt1)/EFI/ubuntu      # read grub at /boot/efi/EFI/ubuntu/grub.cfg.

Grub will first probe the /dev/nvme0n1p1, which is the FAT format. When
trying FAT fs, the mount is successful, but there is a check that if any
files under the mount patch(/boot/efi) timestamp exceeds 2038, probe
will fail, and try next type FS(for example, ext2...). Ultimately, the
probe will fail and can not read the grub.cfg and show the grub menu,
then enter the grub cmdline.

It's easy to reproduce:
    touch -d "2038-02-20" /boot/efi/EFI
    reboot.   # After reboot, enter the grub cmdline.

Can mannel boot the setup success:
    set prefix=(hd0,gpt2)/boot/grub   # set the "grub.cfg" on the second partition, it's ext2 format. The path is:  "/boot/grub/grub.cfg". Actually "/boot/efi/EFI/ubuntu/grub.cfg" redirected to it.
    insmod linux
    insmod normal
    normal         # Boot linux success.

There already is a fix in the master branch:  e43f3d93b fs/fat: Don't error when mtime is 0. 
I have tested it, and it works. We need to include this patch in the latest Ubuntu grub-2.06 code.

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: linux-bluefield (Ubuntu)
     Importance: Undecided
         Status: New

-- 
grub 2.06  prob fat fs fail.
https://bugs.launchpad.net/bugs/2098641
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