firmware: raspberrypi: Use dev_err_probe() to simplify code

In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.

Signed-off-by: Yuan Can <yuancan@huawei.com>
Link: https://lore.kernel.org/r/20220924025041.29389-1-yuancan@huawei.com


Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>