realtek: dsa: rtl839x: fix uninitialized global access

realtek: dsa: rtl839x: fix uninitialized global access

Setup for DSA QOS on RTL839x accesses unitialized memory. For some
reason the handover of the priv structure was realized via global
intermediate variable switch_priv. During refactoring for adbb9a6
("realtek: dsa: rtl83xx: fix init section mismatch") this was not
noticed. Since then RTL839x devices crash during startup.

Fix this by using standard handover via function parameters.

Fixes: adbb9a6 ("realtek: dsa: rtl83xx: fix init section mismatch")
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/21703
Signed-off-by: Robert Marko <robimarko@gmail.com>