mark context switch wrmsr path unlikely

diff -urpN --exclude-from=/home/davej/.exclude bk-linus/include/asm-i386/processor.h linux-2.5/include/asm-i386/processor.h
--- bk-linus/include/asm-i386/processor.h	2003-03-21 12:53:30.000000000 +0000
+++ linux-2.5/include/asm-i386/processor.h	2003-03-21 13:45:20.000000000 +0000
@@ -419,7 +419,7 @@ static inline void load_esp0(struct tss_
 {
 	tss->esp0 = esp0;
 	/* This can only happen when SEP is enabled, no need to test "SEP"arately */
-	if (tss->ss1 != __KERNEL_CS) {
+	if ((unlikely(tss->ss1 != __KERNEL_CS))) {
 		tss->ss1 = __KERNEL_CS;
 		wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
 	}