realtek: update rtl83xx switch driver to the updated DSA API

realtek: update rtl83xx switch driver to the updated DSA API

This fixes:
  CC      drivers/net/dsa/rtl83xx/dsa.o
drivers/net/dsa/rtl83xx/dsa.c:1274:22: error: initialization of 'enum dsa_tag_protocol (*)(struct dsa_switch *, int,  enum dsa_tag_protocol)' from incompatible pointer type 'enum dsa_tag_protocol (*)(struct dsa_switch *, int)' [-Werror=incompatible-pointer-types]
  .get_tag_protocol = rtl83xx_get_tag_protocol,
                      ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/dsa/rtl83xx/dsa.c:1274:22: note: (near initialization for 'rtl83xx_switch_ops.get_tag_protocol')
drivers/net/dsa/rtl83xx/dsa.c:1316:22: error: initialization of 'enum dsa_tag_protocol (*)(struct dsa_switch *, int,  enum dsa_tag_protocol)' from incompatible pointer type 'enum dsa_tag_protocol (*)(struct dsa_switch *, int)' [-Werror=incompatible-pointer-types]
  .get_tag_protocol = rtl83xx_get_tag_protocol,
                      ^~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 1f5024aa73fc ("kernel: backport b53/bcm_sf2 changes from v5.6")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>