can: mcp251xfd: mcp251xfd_probe(): fix an error pointer dereference in probe

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

can: mcp251xfd: mcp251xfd_probe(): fix an error pointer dereference in probe

When we converted this code to use dev_err_probe() we accidentally removed a return. It means that if devm_clk_get() it will lead to an Oops when we call clk_get_rate() on the next line.