bcm4008: prepare to work on kernel 6.6

bcm4008: prepare to work on kernel 6.6

Don't add KERNEL_TESTING_PATCHVER yet as there are some issues with it.

On TP-Link Archer C2300 serial console seems to stop working after
preinit:
> Press the [f] key and hit [enter] to enter failsafe mode
> Press the [1], [2], [3] or [4] key and hit [enter] to select the de�

On Netgear R8000P XHCI causes external abort:
[    2.139586] Internal error: synchronous external abort: 0000000096000210 [#1] SMP
[    2.147212] Modules linked in: xhci_plat_hcd(+) xhci_hcd ohci_platform ohci_hcd fsl_mph_dr_of ehci_platform ehci_fsl ehci_hcd gpio_button_hotplug(O) usbcore nls_base usb_common crc32c_generic
[    2.164774] CPU: 0 PID: 358 Comm: kmodloader Tainted: G           O       6.6.22 #0
[    2.172658] Hardware name: Netgear R8000P (DT)
[    2.177229] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    2.184395] pc : xhci_gen_setup+0x80/0x34c [xhci_hcd]
[    2.189591] lr : xhci_gen_setup+0x74/0x34c [xhci_hcd]
[    2.194788] sp : ffffffc0815d37b0
[    2.198194] x29: ffffffc0815d37b0 x28: ffffff8002000000 x27: ffffff8001172d88
[    2.205540] x26: ffffff8002000000 x25: 0000000000000000 x24: ffffffc078b603c0
[    2.212888] x23: ffffffc078b2a008 x22: ffffff8001172c10 x21: ffffff8002000000
[    2.220235] x20: ffffff8002000000 x19: ffffff8002000250 x18: 0000000000000000
[    2.227582] x17: 626d756e20737562 x16: 2064656e67697373 x15: ffffffffffffffff
[    2.234929] x14: ffffff80019e9915 x13: ffffff80019e9913 x12: 00000000ffffffea
[    2.242276] x11: 00000000ffffefff x10: 0000000000000062 x9 : 00000000ffffffd0
[    2.246760] bcm63138_nand ff801800.nand-controller: timeout waiting for command 0x4
[    2.249623] x8 : 0000000000000073 x7 : ffffffc0815d37c0 x6 : 0000000000000075
[    2.257513] bcm63138_nand ff801800.nand-controller: intfc status c00000e0
[    2.264855] x5 : 0000000000000081 x4 : 0000000000000000 x3 : ffffff8001b61800
[    2.279193] x2 : ffffffc080b5d000 x1 : ffffff80020003a8 x0 : ffffff8002000398
[    2.286540] Call trace:
[    2.289048]  xhci_gen_setup+0x80/0x34c [xhci_hcd]

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>