tpm: tpm_ibmvtpm: fix kdoc warnings

Remove redundant lines in the kdoc:

Fixes kdoc warnings:

drivers/char/tpm/tpm_ibmvtpm.c:42: warning: Cannot understand  *
 on line 42 - I thought it was a doc line
drivers/char/tpm/tpm_ibmvtpm.c:57: warning: Cannot understand  *
 on line 57 - I thought it was a doc line

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>