tpm_crb: Check ACPI_COMPANION() against NULL during probe

tpm_crb: Check ACPI_COMPANION() against NULL during probe

Every platform driver can be forced to match a device that doesn't match
its list of device IDs because of device_match_driver_override(), so
platform drivers that rely on the existence of a device's ACPI companion
object need to verify its presence.

Accordingly, add a requisite ACPI_COMPANION() check against NULL to the
tpm_crb driver.

Fixes: 48fe2cddc85c ("tpm_crb: Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/2848144.mvXUDI8C0e@rafael.j.wysocki
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>