xilinx: fru: Replace spaces with \0 in detected revision

xilinx: fru: Replace spaces with \0 in detected revision

Also fix board revision field where spaces are used instead of \0.
The same change was done for board name by commit b8b3c1b84969 ("xilinx:
fru: Replace spaces with \0 in detected name").

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/e069e5134e57899e859786ad8ba48721df6df752.1653911444.git.michal.simek@amd.com