[U-Boot] fs: fat: Fix warning in normalize_longname()

[Alexander Graf]

> As observed with clang:
> fs/fat/fat_write.c:1024:13: warning: comparison of constant 128
>       with expression of type 'char' is always false
>       [-Wtautological-constant-out-of-range-compare]
>                 if ((0x80 <= c) && (c <= 0xff))
>                      ~~~~ ^  ~
> fs/fat/fat_write.c:1024:25: warning: comparison of constant 255
>       with expression of type 'char' is always true
>       [-Wtautological-constant-out-of-range-compare]
>                 if ((0x80 <= c) && (c <= 0xff))
>                                     ~ ^  ~~~~
> 
> Fixes: 25bb9dab14f4 ("fs: fat: check and normalize file name")
> Cc: AKASHI Takahiro <takahiro.akashi at linaro.org>
> Cc: Alexander Graf <agraf at suse.de>
> Signed-off-by: Tom Rini <trini at konsulko.com>

Thanks, applied to efi-2018.11

Alex