char: tpm: Deletion of unnecessary checks before the function call "tpm_dev_vendor_release"

The tpm_dev_vendor_release() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>