x86: convert rdtscll() to use __native_read_tsc

Impact: micro-optimization

Is there any reason why x86 rdtscll have to use the out of line
function instead of inline __native_read_tsc()?  native_read_tsc and
__native_read_tsc is essentially the same functions.

Patch to let x86 rdtscll() to use the inline version of read_tsc.
Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/msr.h

@@ -181,10 +181,10 @@ static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
 }
 
 #define rdtscl(low)						\
-	((low) = (u32)native_read_tsc())
+	((low) = (u32)__native_read_tsc())
 
 #define rdtscll(val)						\
-	((val) = native_read_tsc())
+	((val) = __native_read_tsc())
 
 #define rdpmc(counter, low, high)			\
 do {							\