sh: oprofile: Fix up and extend op_name_from_perf_id().

op_name_from_perf_id() currently returns a local variable, which isn't
terribly productive. As we only handle a single PMU case for now, simply
allocate and free the string from the arch init/exit context and have
op_name_from_perf_id() hand back the cached string.

This also takes UTS_MACHINE in to account, given that we build for
multiple architectures.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/sh4/perf_event.c

@@ -225,7 +225,7 @@ static void sh7750_pmu_enable_all(void)
 }
 
 static struct sh_pmu sh7750_pmu = {
-	.name		= "SH7750",
+	.name		= "sh7750",
 	.num_events	= 2,
 	.event_map	= sh7750_event_map,
 	.max_events	= ARRAY_SIZE(sh7750_general_events),

arch/sh/kernel/cpu/sh4a/perf_event.c

@@ -259,7 +259,7 @@ static void sh4a_pmu_enable_all(void)
 }
 
 static struct sh_pmu sh4a_pmu = {
-	.name		= "SH-4A",
+	.name		= "sh4a",
 	.num_events	= 2,
 	.event_map	= sh4a_event_map,
 	.max_events	= ARRAY_SIZE(sh4a_general_events),