[PATCH] Fix prefetch patching in 2.5-bk

Brown paperbag time. I forgot to take the modrm byte in account
with the prefetch patch replacement.  With 3.2 it worked because
it used the right registers in my configuration.

But gcc 2.96 uses a different register in __dpath and the prefetch becomes
4 bytes with modrm and the original nop needs to be as long as that too.

include/asm-i386/processor.h

@@ -564,7 +564,7 @@ static inline void rep_nop(void)
 #define ARCH_HAS_PREFETCH
 extern inline void prefetch(const void *x)
 {
-	alternative_input(ASM_NOP3,
+	alternative_input(ASM_NOP4,
 			  "prefetchnta (%1)",
 			  X86_FEATURE_XMM,
 			  "r" (x));
@@ -578,7 +578,7 @@ extern inline void prefetch(const void *x)
    spinlocks to avoid one state transition in the cache coherency protocol. */
 extern inline void prefetchw(const void *x)
 {
-	alternative_input(ASM_NOP3,
+	alternative_input(ASM_NOP4,
 			  "prefetchw (%1)",
 			  X86_FEATURE_3DNOW,
 			  "r" (x));