tools/rtla: Fix unassigned nr_cpus

In recently introduced timerlat_free(),
the variable 'nr_cpus' is not assigned.

Assign it with sysconf(_SC_NPROCESSORS_CONF) as done elsewhere.
Remove the culprit: -Wno-maybe-uninitialized. The rest of the
code is clean.

Signed-off-by: Costa Shulyupin <[e-mail]>
Reviewed-by: Tomas Glozar <[e-mail]>
Fixes: 2f3172f9dd58 ("tools/rtla: Consolidate code between osnoise/timerlat and hist/top")
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Tomas Glozar <[e-mail]>

tools/tracing/rtla/Makefile.rtla

···
 FOPTS		:= -flto=auto -ffat-lto-objects -fexceptions -fstack-protector-strong	\
 		-fasynchronous-unwind-tables -fstack-clash-protection
 WOPTS		:= -O -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2		\
-		-Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized
+		-Wp,-D_GLIBCXX_ASSERTIONS
 
 ifeq ($(CC),clang)
   FOPTS		:= $(filter-out -flto=auto -ffat-lto-objects, $(FOPTS))

tools/tracing/rtla/src/timerlat.c

···
 void timerlat_free(struct osnoise_tool *tool)
 {
 	struct timerlat_params *params = to_timerlat_params(tool->params);
-	int nr_cpus, i;
+	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+	int i;
 
 	timerlat_aa_destroy();
 	if (dma_latency_fd >= 0)