can: mcp251xfd: add workaround for errata 5

can: mcp251xfd: add workaround for errata 5

According to Errata DS80000789E 5 writing IOCON register using one SPI
write command clears LAT0/LAT1.

Errata Fix/Work Around suggests to write registers with single byte write
instructions. However, it seems that every write to the second byte
causes the overwrite of LAT0/LAT1.

Never write byte 2 of IOCON register to avoid clearing of LAT0/LAT1.

Signed-off-by: Gregor Herburger <gregor.herburger@ew.tq-group.com>
Tested-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20251001091006.4003841-4-viken.dadhaniya@oss.qualcomm.com
[mkl: add missing MCP251XFD_REG_IOCON_GPIO_MASK]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>