platform: mellanox: mlx-platform: Add reset cause attribute

Extend IO registers description for some system types with reset cause
attribute "reset_swb_dc_dc_pwr_fail" to indicate reset caused by switch
board DC-DC power failure.
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Michael Shych <michaelsh@nvidia.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230822113451.13785-6-vadimp@nvidia.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/mlx-platform.c

@@ -3558,6 +3558,12 @@ static struct mlxreg_core_data mlxplat_mlxcpld_default_ng_regs_io_data[] = {
 		.mask = GENMASK(7, 0) & ~BIT(2),
 		.mode = 0444,
 	},
+	{
+		.label = "reset_swb_dc_dc_pwr_fail",
+		.reg = MLXPLAT_CPLD_LPC_REG_RESET_CAUSE_OFFSET,
+		.mask = GENMASK(7, 0) & ~BIT(3),
+		.mode = 0444,
+	},
 	{
 		.label = "reset_from_asic",
 		.reg = MLXPLAT_CPLD_LPC_REG_RESET_CAUSE_OFFSET,