Fixed wrong cfg used for mhmpcounter29_csr_access tests

Created by: silabs-hfegran

The mhpmcounter29_csr_access_test_* should be run with NUM_MHPMCOUNTERS=29.

Full regression changed to use the num_hpmcounter_29 config for these tests,
and added support for bitmanip instructions to this cfg.

Signed-off-by: Henrik Fegran Henrik.Fegran@silabs.com