[entropy_src/rtl] Window_cntr disable timing
[entropy_src/rtl] Window_cntr disable timing

This commit delays the clear of the window_cntr after disable until the
last data admitted has cleared the health checks

Signed-off-by: Martin Lueker-Boden <7e82c17fafb3b7b91b3c3396a2f21a060e5a6c3d@wdc.com>

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