lib, lscpu: fix const qualifier discarded warnings in bsearch

lib, lscpu: fix const qualifier discarded warnings in bsearch

Fix compilation warnings from newer compilers with stricter
const-correctness checks. When bsearch() searches in const arrays,
the result pointer must also be const to avoid discarding the
const qualifier.

Fixed in:
- lib/color-names.c: searching in static const basic_schemes[]
- sys-utils/lscpu-cputype.c: searching in const pattern arrays

The warnings were:
  lib/color-names.c:62:13: error: assignment discards 'const'
  qualifier from pointer target type
  [-Werror=discarded-qualifiers]

Signed-off-by: Karel Zak <kzak@redhat.com>