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/private/bionic_vdso.h b/libc/private/bionic_vdso.h
index 8fd0743..2d11cd6 100644
--- a/libc/private/bionic_vdso.h
+++ b/libc/private/bionic_vdso.h
@@ -34,7 +34,7 @@
 #if defined(__aarch64__)
 #define VDSO_CLOCK_GETTIME_SYMBOL "__kernel_clock_gettime"
 #define VDSO_GETTIMEOFDAY_SYMBOL  "__kernel_gettimeofday"
-#elif defined(__arm__) || defined(__i386__) || defined(__x86_64__)
+#else
 #define VDSO_CLOCK_GETTIME_SYMBOL "__vdso_clock_gettime"
 #define VDSO_GETTIMEOFDAY_SYMBOL  "__vdso_gettimeofday"
 #endif