perf machine: Fix paranoid check in machine__set_kernel_mmap()

The machine__set_kernel_mmap() is to setup addresses of the kernel map
using external info.  But it has a check when the address is given from
an incorrect input which should have the start and end address of 0
(i.e. machine__process_kernel_mmap_event).

But we also use the end address of 0 for a valid input so change it to
check both start and end addresses.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20180219101936.GD1583@sejong


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>