When an 'after' map is generated the 'new' map must be before it so
terminate iterating and don't resort. If the entry 'pos' is entirely
overlapped by the 'new' mapping then don't remove and insert the
mapping, just replace - again to remove sorting.

For a perf report on a perf.data file containing overlapping mappings
the time numbers are:

Before:
real    0m9.856s
user    0m9.637s
sys     0m0.204s

After:
real    0m5.894s
user    0m5.650s
sys     0m0.231s
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@arm.com>
Cc: Steinar H . Gunderson <sesse@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240521165109.708593-3-irogers@google.com