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

Change-Id: I9d016ee8e8329cccf244d27c336d9524348af996
diff --git a/libc/arch-x86/bionic/futex_x86.S b/libc/arch-x86/bionic/futex_x86.S
index 36a28e8..fa33758 100644
--- a/libc/arch-x86/bionic/futex_x86.S
+++ b/libc/arch-x86/bionic/futex_x86.S
@@ -1,5 +1,5 @@
+#include <asm/unistd.h>
 #include <machine/asm.h>
-#include <sys/linux-syscalls.h>
 
 #define FUTEX_WAIT 0
 #define FUTEX_WAKE 1