tpm: Use managed allocation for bios event log

Since the bios event log is freed in the device release function,
let devres handle the deallocation. This will allow other memory
allocation/mapping functions to be used for the bios event log.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>