[kmac] Remove sideload key valid condition
[kmac] Remove sideload key valid condition

While adding multiple app interfaces, sideloaded key valid check
condition in the StIdle state wasn't removed even the condition is
checked in the StAppCfg state.

This commit removes the condition, so that the AppIntf that does not use
KMAC can move forward without the valid sideloaded key.

This issue is reported by @udinator (Issue #6344 )

Signed-off-by: Eunchan Kim <cb7bc7ceb22698f298c67faa994fd9ddf3cab298@opentitan.org>

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