perf report: Remove the time slices number limitation

perf report: Remove the time slices number limitation

Previously it was only allowed to use at most 10 time slices in 'perf
report --time'.

This patch removes this limitation.
For example, following command line is OK (12 time slices)

perf report --stdio --time 1%/1,1%/2,1%/3,1%/4,1%/5,1%/6,1%/7,1%/8,1%/9,1%/10,1%/11,1%/12

Signed-off-by: Jin Yao <[email protected]>
Suggested-by: Arnaldo Carvalho de Melo <[email protected]>
Reviewed-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ No need to check for NULL to call free, use zfree ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>