staging: keucr: Use memcmp() & memcpy() instead of custom String[Cmp|Copy] functions

This patchset make some cleanup to staging/keucr. Use memcmp and memcpy instead of custom functions. Also some style cleanups.

The patches in this patchset are the following:

[PATCH 1/2] staging: keucr: Use memcmp() instaed of custom StringCmp() and some style cleanups [PATCH 2/2] staging: keucr: Use memcpy() instad of custom StringCopy() and some style cleanups [PATCH 3/4] staging: keucr: Delete StringCmp() and StringCopy custom functions [PATCH 4/4] staging: keucr: Delete use kernel strcmp() & strcpy() from TODO file