hdcp_qseecom: Maintain repeater_flag appropriately

The repeater_flag is set to true on receiving the first appropriate
message from repeater and then again is set to false even if repeater's
connection is active. Due to this, compliance tests for repeater
scenarios fail.

Change-Id: I8fad7d1aad1d71a70534ed3a6237ad2a15e5b39e
Signed-off-by: Tanwee Kausar <tkausar@codeaurora.org>