Merge patch series "can: gs_usb: hardware timestamp support"

Marc Kleine-Budde <mkl@pengutronix.de> says:

after noticing that the gs_usb firmware sends timestamps on the TX,
too, I updated the driver and squashed the 2nd patch. Also added
proper endianness handling to gs_usb_get_timestamp(). I allowed to add
myself as Co-developed-by.

Changes since v2: https://lore.kernel.org/all/20220827092545.2971240-1-mkl@pengutronix.de
- new patch 1/2: use common spelling of GS_USB in macros
- squashed both old patches into now 2/2
- use GS_USB instead of GSUSB in macros
- gs_usb_get_timestamp(): renamed from gs_usb_get_sof_timestamp()
- gs_usb_get_timestamp(): take care of endianness
- gs_usb_skb_set_timestamp(): renamed from gs_usb_set_timestamp()
- gs_usb_set_timestamp(): add new function to add timestamp to skb
  from struct gs_host_frame
- add support for TX timestamps
- gs_can_eth_ioctl(): return -EOPNOTSUPP if device doesn't support
  GS_CAN_FEATURE_HW_TIMESTAMP
- gs_usb_get_ts_info(): renamed from gs_usb_get_ts_info_hwts()
- gs_usb_get_ts_info(): call can_ethtool_op_get_ts_info_hwts() if
  device supports GS_CAN_FEATURE_HW_TIMESTAMP, call
  ethtool_op_get_ts_info() otherwise

Changes since v1: https://lore.kernel.org/all/20220826104629.2837024-1-mkl@pengutronix.de
- add new includes sorted
- adjust multi line comment style
- don't use 1e6, but 1 * HZ_PER_MHZ, to fix sparse warning
- use __le32 instead of u32 in struct classic_can_ts and canfd_ts
- place _ts in front of _quirk in union in struct gs_host_frame
- gs_usb_get_sof_timestamp(): pass "const struct gs_can *dev" as 1st
  argument, not struct net_device *netdev, simplify return handling
- gs_usb_timestamp_init(), gs_usb_timestamp_stop(),
  gs_usb_get_ts_info_hwts(): make static
- gs_usb_timestamp_init(): increase cc->shift to maximize precision
- fix long lines, remove braces {} for single statement blocks
- gs_can_open(): move check for GS_CAN_FEATURE_HW_TIMESTAMP after all
  ctrlmode checks
- gs_can_open(): move start polling sof timestamp after kfree(dm)
- gs_can_close(): move stop polling sof timestamp to be symmetric with
  respect to gs_can_open()
- gs_usb_probe(): make calculation of dev->hf_size_rx more robust

Link: https://lore.kernel.org/all/20220827221548.3291393-1-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>