[entropy_src/rtl] Use mubi4_test_false_loose
[entropy_src/rtl] Use mubi4_test_false_loose

Changing the mubi check to "false_loose" for the register lock
function.

Signed-off-by: Mark Branstad <d7ca710cc6ec5dc810c866dae5369b19445fbeef@wdc.com>
Signed-off-by: Michael Schaffner <a005a2d3342a687ea2d05360c953107acbe83e08@opentitan.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan