[PATCH] powerpc/perf: fix missing is_sier_aviable() during build

[Madhavan Srinivasan <maddy@linux.ibm.com>]

Compilation error:

arch/powerpc/perf/perf_regs.c:80:undefined reference to `.is_sier_available'

Currently is_sier_available() is part of core-book3s.c.
But then, core-book3s.c is added to build based on
CONFIG_PPC_PERF_CTRS. A config with CONFIG_PERF_EVENTS
and without CONFIG_PPC_PERF_CTRS will have a build break
because of missing is_sier_available(). Patch adds
is_sier_available() in asm/perf_event.h to fix the build
break for configs missing CONFIG_PPC_PERF_CTRS.

Fixes: 333804dc3b7a9 ('powerpc/perf: Update perf_regs structure to include SIER")
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
 arch/powerpc/include/asm/perf_event.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/include/asm/perf_event.h b/arch/powerpc/include/asm/perf_event.h
index eed3954082fa..1e8b2e1ec1db 100644
--- a/arch/powerpc/include/asm/perf_event.h
+++ b/arch/powerpc/include/asm/perf_event.h
@@ -12,6 +12,8 @@
 
 #ifdef CONFIG_PPC_PERF_CTRS
 #include <asm/perf_event_server.h>
+#else
+static inline bool is_sier_available(void) { return false; }
 #endif
 
 #ifdef CONFIG_FSL_EMB_PERF_EVENT
-- 
2.26.2