mips: add mips64le support for atomic_incs and annotate_hbefore tests

Add mips64-le implementation of:

- atomic_add_8bit
- atomic_add_16bit
- atomic_add_32bit
- atomic_add_64bit
- do_acasW

Minor fixes for mips32 implementations are included as well.

These functions are needed to execute atomic_incs and annotate_hbefore
tests on mips64le.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13357 a5019735-40e9-0310-863c-91ae7b9d1cf9
mips: enable several system call wrappers on mips64

Enable wrappers on mips64 for the following calls:

- dup3
- accept4
- epoll_create1
- timerfd_settime
- newfstatat

Also, allow additional flock64 values in sys_fcntl for mips64.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13358 a5019735-40e9-0310-863c-91ae7b9d1cf9