net: marvell: prestera: bump supported firmware version to 3.0

New firmware version has some ABI and feature changes like:

    - LAG support
    - initial L3 support
    - changed events handling logic
Signed-off-by: NVadym Kochan <vkochan@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/prestera/prestera_pci.c

@@ -14,7 +14,7 @@
 
 #define PRESTERA_MSG_MAX_SIZE 1500
 
-#define PRESTERA_SUPP_FW_MAJ_VER	2
+#define PRESTERA_SUPP_FW_MAJ_VER	3
 #define PRESTERA_SUPP_FW_MIN_VER	0
 
 #define PRESTERA_FW_PATH_FMT	"mrvl/prestera/mvsw_prestera_fw-v%u.%u.img"