The .shutdown(), .remove(), and power management callbacks are never called
unless .probe() has already returned success, which means it has set
drvdata to a non-NULL pointer, so "dev" can never be NULL in the other
callbacks.

Remove the unnecessary checks.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20240229181300.352077-3-helgaas@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>