sysinfo: Provide a default driver to set SMBIOS values

Some boards want to specify the manufacturer or product name but do not
need to have their own sysinfo driver.

Add a default driver which provides a way to specify this SMBIOS
information in the devicetree, without needing any board-specific
functionality.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/lib/Kconfig b/lib/Kconfig
index 8f48753..fdc35a9 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -658,6 +658,9 @@
 
 	  Check http://www.dmtf.org/standards/smbios for details.
 
+	  See also SMBIOS_SYSINFO which allows SMBIOS values to be provided in
+	  the devicetree.
+
 config SMBIOS_MANUFACTURER
 	string "SMBIOS Manufacturer"
 	depends on GENERATE_SMBIOS_TABLE