acpigen: Add ability to auto-generate _DSM Function 0

Since the value returned by _DSM function 0 for a given UUID is trivial
to calculate, add the ability to do so to the
acpigen_write_dsm() functions.

Change-Id: Id9be050442485b42202cf91649aa94e56f35032a
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56459
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/include/acpi/acpigen.h

@@ -441,11 +441,14 @@ void acpigen_write_create_qword_field(uint8_t op, size_t byte_offset, const char
  * This function takes as input uuid for the device, set of callbacks and
  * argument to pass into the callbacks. Callbacks should ensure that Local0 and
  * Local1 are left untouched. Use of Local2-Local7 is permitted in callbacks.
+ * If the first callback is NULL, then a default implementation of Function 0
+ * will be autogenerated, returning a package of bits corresponding to the
+ * function callbacks that are non-NULL.
  */
 void acpigen_write_dsm(const char *uuid, void (**callbacks)(void *),
 		       size_t count, void *arg);
-void acpigen_write_dsm_uuid_arr(struct dsm_uuid *ids, size_t count);
 
+void acpigen_write_dsm_uuid_arr(struct dsm_uuid *ids, size_t count);
 /*
  * Generate ACPI AML code for _CPC (Continuous Performance Control).
  * Execute the package function once to create a global table, then