w1: add 1-wire master driver for IP block found in SGI ASICs

Starting with SGI Origin machines nearly every new SGI ASIC contains
an 1-Wire master. They are used for attaching One-Wire prom devices,
which contain information about part numbers, revision numbers,
serial number etc. and MAC addresses for ethernet interfaces.
This patch adds a master driver to support this IP block.
It also adds an extra field dev_id to struct w1_bus_master, which
could be in used in slave drivers for creating unique device names.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Link: https://lore.kernel.org/r/20190831082623.15627-2-tbogendoerfer@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/platform_data/sgi-w1.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SGI One-Wire (W1) IP
+ */
+
+#ifndef PLATFORM_DATA_SGI_W1_H
+#define PLATFORM_DATA_SGI_W1_H
+
+struct sgi_w1_platform_data {
+	char dev_id[64];
+};
+
+#endif /* PLATFORM_DATA_SGI_W1_H */