debug/ltrace: fix building for mips

ltrace 0.5.3 currently fails to build for target mips because MY_TARGET
(introduced by patches/ltrace/0.5.3/150-allow-configurable-arch.patch)
is set to 'mips' via CT_ARCH, while the mips specific stuff in ltrace
(0.5.3) is stored under sysdeps/linux-gnu/mipsel:

result: *** No rule to make target `mips/arch.h', needed by `sysdep.h'.
Stop.

The following patch fixes this issue

Signed-off-by: "Horst Kronstorfer" <horst.kronstorfer@aon.at>
[yann.morin.1998@anciens.enib.fr: reformat commit log]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from 2115901c7f07181d92ddbd7dd7ebeaa72e4fb176)

# Configuration file for sstrip tool facility

if OBSOLETE && ! BACKEND && ARCH_BINFMT_ELF

comment "sstrip"

config SSTRIP

    bool

    prompt "sstrip (OBSOLETE)"

    help

      The sstrip utility, to maximise the striping of ELF binaries

      (executables and libraries).

      Buildroot version, forked off the original from ELFkickers.

      This one is somewhat maintained by the buildroot guys.

      Supports big-endian systems.

      NOTE! Please read.

        sstrip is now deprecated in crosstool-NG, as it has a few

        shortcomings. For example: it breaks for PPC targets, it

        does not build on non-ELF hosts (eg. mingw32, MacOS-X...).

endif