rtklib: disable MIPS16 to work around GCC ICE

rtklib: disable MIPS16 to work around GCC ICE

The MIPS variants (mips_24kc, mips_4kec, mipsel_24kc, mipsel_74kc) all
fail to compile preceph.c with an internal compiler error:

  during RTL pass: reload
  src/preceph.c:317:1: internal compiler error:
    in lra_update_fp2sp_elimination, at lra-eliminations.cc:1416

This is a GCC LRA pass bug triggered when compiling with -mips16. Set
PKG_BUILD_FLAGS:=no-mips16 to strip the -mips16 / -minterlink-mips16
flags from CFLAGS for this package, matching the approach already used
by stress-ng for the same class of issue.

Bump PKG_RELEASE since only the build flags change.

Signed-off-by: Alexandru Ardelean <redacted>