remove libdecnumber/dpd/decimal128Local.h

remove libdecnumber/dpd/decimal128Local.h

Commit 72ac97cdfc added two equivalent versions of decimal128Local.h,
one in libdecnumber/dpd/ and another in include/libdecnumber/dpd/.
Being identical by the code, the two files however differs in the
licensing terms.  The one in libdecnumber/dpd/ (which is being
removed by this patch) is licensed as GPL3.1 (plus gcc runtime
exception), which, as far as I know, is not compatible with GPL-2.
This file is not used (it is included from
include/libdecnumber/dpd/decimal128.h, so version in include/ is
used).

More, the version in include/ can also be removed, since none
of the 3 defines from that file are actually used by the code.
Even more, one of the defines from there, decimal128SetSign,
is redefined (to equivalent value) in libdecnumber/dpd/decimal128.c,
but again, never used.

What a mess...

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>