exfat: Simplify exfat_utf8_d_hash() for code points above U+FFFF

Function partial_name_hash() takes long type value into which can be stored
one Unicode code point. Therefore conversion from UTF-32 to UTF-16 is not
needed.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Git-commit: dddf7da3985ee144b46ee287e81e47b9ee8bb980
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: lixiang <lixiang@codeaurora.org>