perf maps: Move kmap::kmaps setup to maps__insert()

perf maps: Move kmap::kmaps setup to maps__insert()

So the kmaps pointer setup is centralized and we do not need to update
it in all those places (2 current places and few more missing) after
calling maps__insert().

Reported-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Tested-by: Kim Phillips <kim.phillips@amd.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200210143218.24948-5-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>