hwlatdetect: fix RDEPENDS to avoid QA failures

When listing python3 as an RDEPENDS, the image will in fact
contain python3-modules, but the QA check fails to get
RPROVIDERS correctly (since the python3 package does not
actually exist), /usr/bin/python3 is provided by the
python3-core package, so by fixing the RDEPENDS and listing
python3-core instead of python3, the QA check works correctly
and we avoid failures.

Signed-off-by: Alejandro Hernandez <alejandro.hernandez@linux.intel.com>