perf_counter: Set the CONFIG_PERF_COUNTERS default to y if CONFIG_PROFILING=y

If user has already enabled profiling support in the kernel
(for oprofile, old-style profiling of ftrace) then offer up
perfcounters with a y default in interactive kconfig sessions.

Still keep it off by default otherwise.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

init/Kconfig

@@ -940,6 +940,7 @@ menu "Performance Counters"
 
 config PERF_COUNTERS
 	bool "Kernel Performance Counters"
+	default y if PROFILING
 	depends on HAVE_PERF_COUNTERS
 	select ANON_INODES
 	help