uclibc: add patches to fix MIPS __SIGRTMAX and SIG127

Add two uClibc 0.9.33.2 patches which fix issues relating to high signal
number handling on MIPS.

The first patch (0056) fixes _NSIG (and as a result __SIGRTMAX) to match
glibc. This fixes GDB on MIPS with uClibc, which cannot handle
__SIGRTMAX == 128 and emits the error:
GDB bug: target.c (gdb_signal_from_host): unrecognized real-time signal
This patch is from uClibc commit 2da958760f79 (MIPS: set _NSIG to
128, not 129. This matches glibc.) and applies without conflicts.

The second patch (0057) fixes the wait status macros to correctly
interpret status 0x007f on MIPS (other arches don't have signal 127).
This patch is from uClibc commit 4a96b9486871 (bits/waitstatus.h:
correctly interpret status 0x007f on MIPS) and applies without
conflicts.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>