drm/panic: Use a decimal fifo to avoid u64 by u64 divide

On 32bits ARM, u64/u64 is not supported [1], so change the algorithm
to use a simple fifo with decimal digits as u8 instead.
This is slower but should compile on all architecture.

Link: https://lore.kernel.org/dri-devel/CANiq72ke45eOwckMhWHvmwxc03dxr4rnxxKvx+HvWdBLopZfrQ@mail.gmail.com/

 [1]
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://lore.kernel.org/dri-devel/CANiq72ke45eOwckMhWHvmwxc03dxr4rnxxKvx+HvWdBLopZfrQ@mail.gmail.com/


Fixes: ccb8ce52 ("ARM: 9441/1: rust: Enable Rust support for ARMv7")
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250418165059.560503-1-jfalempe@redhat.com


Acked-by: Javier Martinez Canillas <javierm@redhat.com>