octeontx2-af: Increase maximum BPID channels

Any NIX interface type can have maximum 256 channels. So increased the
backpressure ID count to 256 so that it can cover cn9k and cn10k SoCs that
have different NIX interface types with varied maximum channels.
Signed-off-by: Radha Mohan Chintakuntla <radhac@marvell.com>
Link: https://lore.kernel.org/r/20240326184514.1628284-1-radhac@marvell.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/marvell/octeontx2/af/mbox.h

@@ -1213,10 +1213,8 @@ struct nix_bp_cfg_req {
 	/* bpid_per_chan = 1 assigns separate bp id for each channel */
 };
 
-/* PF can be mapped to either CGX or LBK interface,
- * so maximum 64 channels are possible.
- */
-#define NIX_MAX_BPID_CHAN	64
+/* Maximum channels any single NIX interface can have */
+#define NIX_MAX_BPID_CHAN	256
 struct nix_bp_cfg_rsp {
 	struct mbox_msghdr hdr;
 	u16	chan_bpid[NIX_MAX_BPID_CHAN]; /* Channel and bpid mapping */