complier.h: add __always_inline and use it in code base

Add a __always_inline macro that wraps __attribute__((always_inline))
and replace current users with the macro, excluding files under
src/vendorcode.

Change-Id: Ic57e474c1d2ca7cc0405ac677869f78a28d3e529
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/28587
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@google.com>
diff --git a/src/include/cpu/amd/mtrr.h b/src/include/cpu/amd/mtrr.h
index b31648d..9661b63 100644
--- a/src/include/cpu/amd/mtrr.h
+++ b/src/include/cpu/amd/mtrr.h
@@ -38,13 +38,14 @@
 
 #if !defined(__PRE_RAM__) && !defined(__ASSEMBLER__)
 
+#include <compiler.h>
 #include <cpu/x86/msr.h>
 
 void amd_setup_mtrrs(void);
 struct device;
 void add_uma_resource_below_tolm(struct device *nb, int idx);
 
-static inline __attribute__((always_inline)) msr_t rdmsr_amd(unsigned int index)
+static __always_inline msr_t rdmsr_amd(unsigned int index)
 {
 	msr_t result;
 	__asm__ __volatile__ (
@@ -55,8 +56,7 @@
 	return result;
 }
 
-static inline __attribute__((always_inline)) void wrmsr_amd(unsigned int index,
-	msr_t msr)
+static __always_inline void wrmsr_amd(unsigned int index, msr_t msr)
 {
 	__asm__ __volatile__ (
 		"wrmsr"