char: tpm: Fix possible memory leak in tpm_bios_measurements_open()

In tpm_bios_measurements_open(), get_device() is called on the device
embedded in struct tpm_chip. In the error path, however, put_device() is
not called. This results in a reference count leak, which prevents the
device from being properly released. This commit makes sure to call
put_device() when the seq_open() call fails.

Cc: stable@vger.kernel.org # +v4.18
Fixes: 9b01b535 ("tpm: Move shared eventlog functions to common.c")
Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>