Replace unnecessary x86 uses of <sys/linux-syscalls.h> with <asm/unistd.h>.

Change-Id: I9d016ee8e8329cccf244d27c336d9524348af996
diff --git a/libc/arch-x86/bionic/clone.S b/libc/arch-x86/bionic/clone.S
index 80e3c75..457cb4a 100644
--- a/libc/arch-x86/bionic/clone.S
+++ b/libc/arch-x86/bionic/clone.S
@@ -1,5 +1,5 @@
+#include <asm/unistd.h>
 #include <machine/asm.h>
-#include <sys/linux-syscalls.h>
 
 // int  __pthread_clone(void* (*fn)(void*), void* tls, int flags, void* arg);
 ENTRY(__pthread_clone)