ddr: altera: Extract scc_mgr_set_hhp_extras()

Move scc_mgr_set_hhp_extras() out of scc_set_bypass_mode() as it
has nothing to do in there. Instead, invoke it from mem_calibrate()
just before invoking scc_set_bypass_mode().

Signed-off-by: Marek Vasut <marex@denx.de>