drop last _syscall6 checks

If your arch does not support _syscall6(), it is broken anyways.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

libc/sysdeps/linux/common/mmap64.c

@@ -17,7 +17,7 @@
 
 /* libc_hidden_proto(mmap) */
 
-# if !defined __NR_mmap2 || !defined _syscall6
+# if !defined __NR_mmap2
 
 /*
  * This version is a stub that just chops off everything at the mmap 32 bit

libc/sysdeps/linux/common/posix_fadvise.c

@@ -23,7 +23,7 @@ int posix_fadvise(int fd, off_t offset, off_t len, int advice)
     return 0;
 }
 
-#if defined __UCLIBC_HAS_LFS__ && (!defined __NR_fadvise64_64 || !defined _syscall6)
+#if defined __UCLIBC_HAS_LFS__ && !defined __NR_fadvise64_64
 strong_alias(posix_fadvise,posix_fadvise64)
 #endif