smbios: get_str_from_dt() - add sysinfo_id description

Add description for parameter sysinfo_id of function get_str_from_dt().

Fixes: 07c9e683a484 ("smbios: Allow a few values to come from sysinfo")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/smbios.c b/lib/smbios.c
index 7bd9805..11b7611 100644
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -207,6 +207,7 @@
  *
  * @ctx:	context for writing the tables
  * @prop:	property to write
+ * @sysinfo_id: unique identifier for the string value to be read
  * @dval:	Default value to use if the string is not found or is empty
  * Return:	0 if not found, else SMBIOS string number (1 or more)
  */