ipq40xx: ipqess: do not free ipqess_init

ipq40xx: ipqess: do not free ipqess_init

If this function is marked as __init, kernel will splat when driver is
(re)bind
echo "c080000.ethernet">/sys/bus/platform/drivers/ipqess-edma/unbind
echo "c080000.ethernet">/sys/bus/platform/drivers/ipqess-edma/bind

Example with additional print messages, functions at boot:
[    2.039468] ipqess-edma c080000.ethernet: ipqess_axi_probe pre register_netdev
[    2.039530] ipqess-edma c080000.ethernet: *netdev: c27d2000
[    2.045609] ipqess-edma c080000.ethernet: &ipqess_init: c0d1e28c
[    2.051122] ipqess_init
[    2.057338] netdev: c27d2000
[    2.059492] ess = netdev_priv: c27d2500
[    2.062615] ess->pdev: c2138c00
[    2.066174] ess->pdev->dev: c2138c10
[    2.069314] ess->pdev->dev.of_node: ef6f6368
[    2.073120] ess->pdev->dev.of_node: /soc/ethernet@c080000

fails (bind) after unbind:
[   34.987948] ipqess-edma c080000.ethernet: ipqess_axi_probe pre register_netdev
[   34.988012] ipqess-edma c080000.ethernet: *netdev: c27d6000
[   34.994088] ipqess-edma c080000.ethernet: &ipqess_init: c0d1e28c
[   34.999652] 8<--- cut here ---
[   35.005802] Unable to handle kernel paging request at virtual address c0d1e28c when execute
[   35.008676] [c0d1e28c] *pgd=80c1941e(bad)
[   35.016918] Internal error: Oops: 8000000d [#1] SMP ARM

Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au>
Link: https://github.com/openwrt/openwrt/pull/15831
Signed-off-by: Robert Marko <robimarko@gmail.com>