Update tpm2_clearcontrol.1.md
Update tpm2_clearcontrol.1.md

1. Add more description for the purpose of the tool
2. Add information on the revamped options for the tool choose hierarchy and
   ability to set and clear disableClear effectively blocking and unblocking
   lockout hierachy ability to perform tpm clear operation

Signed-off-by: Imran Desai <d01faadd01d89088a38277c634ffb396f2b368f8@intel.com>

01org/tpm2.0-tools,01org/tpm2.0-tools,01org/tpm2.0-tools