tpm_tis: extra chip->ops check on error path in tpm_tis_core_init

Found by smatch:
drivers/char/tpm/tpm_tis_core.c:1088 tpm_tis_core_init() warn:
 variable dereferenced before check 'chip->ops' (see line 979)

'chip->ops' is assigned in the beginning of function
in tpmm_chip_alloc->tpm_chip_alloc
and is used before first possible goto to error path.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>