Bug#1092826: raspi-firmware: read-write mount of root filesystem prevents fsck at boot on trixie

[Ryutaroh Matsumoto]

Control: severity -1 minor

Since this issue does not happen with ext4 root fs as it is fsck'ed by
/usr/share/initramfs-tools/scripts/functions,
I downgrade its severity to minor.
Read-write mount of root fs still seems problematic when initramfs does not run 
fsck,
for example when /usr/lib/klibc/bin/fstype does not recognize type of root fs.
Ryutaroh