[conn/clk] Update otbn clk connection
[conn/clk] Update otbn clk connection

OTBN EDN clk is updated to connect to `clk_main_secure` from clkmgr.

Signed-off-by: Cindy Chen <399ad771a111eac8923348b1e2af093034e5d4f1@opentitan.org>

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