valgrind: rename patches without version in the filename

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
valgrind: bump to 3.8.1

Status of the patches:

 * valgrind-compiler-check.patch, no longer needed, merged upstream.

 * valgrind-dont-include-a-out-header.patch, kept, just refreshed

 * valgrind-fix-ccache-support.patch, adapted to the newer Valgrind
   release.

 * valgrind-largefile.patch, kept, just refreshed

 * valgrind-more-ioctls.patch, removed. Most of it was merged
   upstream. This patch was anyway a feature addition, so it shouldn't
   be kept in Buildroot.

 * valgrind-workaround-SIGSEGV-on-PPC.patch, kept as is, just
   refreshed.

This bump also fixes the build failure we were experiencing with
Valgrind 3.7.0 against recent Glibc versions.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
valgrind: Enable package on MIPS32

From the Valgrind 3.8.0 release notes:

Support for MIPS32 platforms running Linux.  Valgrind has been
tested on MIPS32 and MIPS32r2 platforms running different Debian
Squeeze and MeeGo distributions.  Both little-endian and big-endian
cores are supported.  The tools Memcheck, Massif and Lackey have
been tested and are known to work. See README.mips for more details.
Unfreeze etna_viv and mesa3d-etna_viv versions

This reverts commit c46157540c6c5141789a594bfd07db86041abe8e.