fs/unicode patches for 5.4-rc1
This includes two fixes for the unicode system for inclusion into Linux
v5.4.
- A patch from Krzysztof Wilczynski solving a build time warning.
- A patch from Colin King making a parsing format static, to reduce
stack size.
Build validated and run time tested using xfstests casefold testcase.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>