selftests/mm: deduplicate second mmap() of 5*PAGE_SIZE at base

selftests/mm: deduplicate second mmap() of 5*PAGE_SIZE at base

The map_fixed_noreplace test does two blocks of test starting from a
mapping of 5 pages at the base address, logging a test result for each
initial mapping.  These are logged with the same test name, causing test
automation software to see two reports for the same test in a single run.
Tweak the log message for the second one to deduplicate.

Link: https://lkml.kernel.org/r/20250518-selftests-mm-map-fixed-noreplace-dup-v1-1-1a11a62c5e9f@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>