Add accept4() syscall

Add accept4() using SYSCALLS.TXT and gensyscall

Change-Id: I6f19f29144186d15d46423e10f2cc4b4223719c6
diff --git a/libc/arch-mips/syscalls/accept4.S b/libc/arch-mips/syscalls/accept4.S
new file mode 100644
index 0000000..ea1dc60
--- /dev/null
+++ b/libc/arch-mips/syscalls/accept4.S
@@ -0,0 +1,19 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(accept4)
+    .set noreorder
+    .cpload t9
+    li v0, __NR_accept4
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    la t9,__set_errno
+    j t9
+    nop
+    .set reorder
+END(accept4)