lib: tpm: Add command to flush resources

lib: tpm: Add command to flush resources

This patch adds a function to the TPM library, which allows U-Boot to
flush resources, e.g. keys, from the TPM.

Signed-off-by: Mario Six <[email protected]>
Reviewed-by: Stefan Roese <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Stefan Roese <[email protected]>