x86: Remove wcsnlen-sse4_1 from wcslen ifunc-impl-list [BZ #28064]

The following commit

commit 6f573a27
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Jun 23 01:19:34 2021 -0400

    x86-64: Add wcslen optimize for sse4.1

Added wcsnlen-sse4.1 to the wcslen ifunc implementation list and did
not add wcslen-sse4.1 to wcslen ifunc implementation list. This commit
fixes that by removing wcsnlen-sse4.1 from the wcslen ifunc
implementation list and adding wcslen-sse4.1 to the ifunc
implementation list.

Testing:
test-wcslen.c, test-rsi-wcslen.c, and test-rsi-strlen.c are passing as
well as all other tests in wcsmbs and string.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 0679442d)