drivers/wifi/generic: Move SMBIOS functions to a separate file

This change reorganizes the WiFi generic driver to move the SMBIOS
functions to a separate file. This change is done to reduce the noise
in generic.c file and improve readability of the file.

Change-Id: I38ed46f5ae1594945d2078b00e8315d9234f36d7
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46859
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/drivers/wifi/generic/wifi_private.h

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _WIFI_GENERIC_PRIVATE_H_
+#define _WIFI_GENERIC_PRIVATE_H_
+
+int smbios_write_wifi(struct device *dev, int *handle, unsigned long *current);
+
+#endif