x86: Support tracing function

Some changes are needed to x86 timer functions to support tracing. Add
these so that the feature works correctly.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h
index 4fdb080..9a2056a 100644
--- a/arch/x86/include/asm/global_data.h
+++ b/arch/x86/include/asm/global_data.h
@@ -40,7 +40,7 @@
 #include <asm-generic/global_data.h>
 
 #ifndef __ASSEMBLY__
-static inline gd_t *get_fs_gd_ptr(void)
+static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void)
 {
 	gd_t *gd_ptr;