misc: tps6594-pfsm: Add NULL pointer check in tps6594_pfsm_probe()

misc: tps6594-pfsm: Add NULL pointer check in tps6594_pfsm_probe()

The returned value, pfsm->miscdev.name, from devm_kasprintf()
could be NULL.
A pointer check is added to prevent potential NULL pointer dereference.
This is similar to the fix in commit 3027e7b15b02
("ice: Fix some null pointer dereference issues in ice_ptp.c").

This issue is found by our static analysis tool.

Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Link: https://lore.kernel.org/r/20250311010511.1028269-1-chenyuan0y@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>