isdn: remove ishexdigit() in regard to isxdigit()
isdn: remove ishexdigit() in regard to isxdigit()

Samll cleanup in drivers/isdn/gigaset/capi.c where own implementation of
isxdigit() has been changed to kernel native one.

Signed-off-by: Andy Shevchenko <f22fd278e04b059f9eabb8d18172c92cd71ea30e@nokia.com>
Acked-by: Tilman Schmidt <dc8b785d67b4628425f4b275427621124af5d812@imap.cc>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas