wifi: iwlwifi: fw: increase fw_version string size

In reality 64 bytes are enough to hold fw version string,
but some compilers can complain (with W=1) that output may be
truncated when building this string with snprintf.
Increase the size to avoid this sort of warnings and state
explicitely that we want the size to be trancated to 32 bytes.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231012153950.f4465b4b4e2b.Idced2e8d63c492872edcde1a3ce2cdd6cc0f8eb7@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>