Documentation/features/lib: Remove arch support status file for 'strncasecmp'

Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NAndrea Parri <andrea.parri@amarulasolutions.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/features/lib/strncasecmp/arch-support.txt

-#
-# Feature name:          strncasecmp
-#         Kconfig:       __HAVE_ARCH_STRNCASECMP
-#         description:   arch provides an optimized strncasecmp() function
-#
-    -----------------------
-    |         arch |status|
-    -----------------------
-    |       alpha: | TODO |
-    |         arc: | TODO |
-    |         arm: | TODO |
-    |       arm64: | TODO |
-    |         c6x: | TODO |
-    |       h8300: | TODO |
-    |     hexagon: | TODO |
-    |        ia64: | TODO |
-    |        m68k: | TODO |
-    |  microblaze: | TODO |
-    |        mips: | TODO |
-    |       nds32: | TODO |
-    |       nios2: | TODO |
-    |    openrisc: | TODO |
-    |      parisc: | TODO |
-    |     powerpc: | TODO |
-    |       riscv: | TODO |
-    |        s390: | TODO |
-    |          sh: | TODO |
-    |       sparc: | TODO |
-    |          um: | TODO |
-    |   unicore32: | TODO |
-    |         x86: | TODO |
-    |      xtensa: | TODO |
-    -----------------------