ltp: set PREFERRED_PROVIDER and rename runtests_noltp.sh script

ltp: set PREFERRED_PROVIDER and rename runtests_noltp.sh script

* ltp installs 2 different runtests_noltp.sh files from different
  directories into /opt/ltp/testcases/bin/runtests_noltp.sh
  last one installed wins and causes unexpected changes in
  buildhistory's files-in-image.txt report, rename them to have
  unique name as other ltp scripts have.

* also define PREFERRED_PROVIDER to resolve note shown when
  building with meta-oe layer:
  NOTE: multiple providers are available for ltp (ltp, ltp-ddt)
  NOTE: consider defining a PREFERRED_PROVIDER entry to match ltp

(From OE-Core rev: ec3bb2c2203b2e8bafc1a631f623f858779e20b7)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>