pds_core: handle unsupported PDS_CORE_CMD_FW_CONTROL result

In the Linux kernel, the following vulnerability has been resolved:

pds_core: handle unsupported PDS_CORE_CMD_FW_CONTROL result

If the FW doesn't support the PDS_CORE_CMD_FW_CONTROL command

the driver might at the least print garbage and at the worst

crash when the user runs the "devlink dev info" devlink command.

This happens because the stack variable fw_list is not 0

initialized which results in fw_list.num_fw_slots being a

garbage value from the stack. Then the driver tries to access

fw_list.fw_names[i] with i >= ARRAY_SIZE and runs off the end

of the array.

Fix this by initializing the fw_list and by not failing

completely if the devcmd fails because other useful information

is printed via devlink dev info even if the devcmd fails.