MIPS: 32/64-bit VDSO support

File libc/SYSCALLS.TXT is updated to generate bionic's system call wrappers
for clock_gettime() & gettimeofday() that will be called if kernel vdso
implementations fail to execute.
The system call wrappers are generated using a python script gensyscalls.py.

Since all architectures support vdso now, there is no more need for conditional
statements regarding supported architectures in libc/bionic/vdso.cpp &
libc/private/bionic_vdso.h files.

Test: builds
Change-Id: I7213f29c179a7929851499d78a72900638ae861a
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
diff --git a/libc/arch-mips/syscalls/__clock_gettime.S b/libc/arch-mips/syscalls/__clock_gettime.S
new file mode 100644
index 0000000..6fad7e9
--- /dev/null
+++ b/libc/arch-mips/syscalls/__clock_gettime.S
@@ -0,0 +1,19 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__clock_gettime)
+    .set noreorder
+    .cpload t9
+    li v0, __NR_clock_gettime
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    la t9,__set_errno_internal
+    j t9
+    nop
+    .set reorder
+END(__clock_gettime)