octeontx2-af: Fix missing check bugs in rvu_cgx.c

In rvu_mbox_handler_cgx_mac_addr_get()
and rvu_mbox_handler_cgx_mac_addr_set(),
the msg is expected only from PFs that are mapped to CGX LMACs.
It should be checked before mapping,
so we add the is_cgx_config_permitted() in the functions.

Fixes: 96be2e0d

 ("octeontx2-af: Support for MAC address filters in CGX")
Signed-off-by: Yingjie Wang <wangyingjie55@126.com>
Reviewed-by: Geetha <sowjanya&lt;gakula@marvell.com>
Link: https://lore.kernel.org/r/1610719804-35230-1-git-send-email-wangyingjie55@126.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>