drivers/acpi: Remove function cast

Remove the function cast in the ACPI_DECLARE_PROBE_ENTRY macro to ensure
that the functions passed as a last parameter to this macro have the
right prototype.

This is an effort to enable -Wcast-function-type in the top-level Makefile
to support Control Flow Integrity builds.
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200530143430.5203-4-oscar.carter@gmx.com

include/linux/acpi.h

@@ -1143,14 +1143,14 @@ struct acpi_probe_entry {
 	kernel_ulong_t driver_data;
 };
 
-#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn)	\
+#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable,	\
+				 valid, data, fn)			\
 	static const struct acpi_probe_entry __acpi_probe_##name	\
-		__used __section(__##table##_acpi_probe_table)		\
-		 = {							\
+		__used __section(__##table##_acpi_probe_table) = {	\
 			.id = table_id,					\
 			.type = subtable,				\
 			.subtable_valid = valid,			\
-			.probe_table = (acpi_tbl_table_handler)fn,	\
+			.probe_table = fn,				\
 			.driver_data = data,				\
 		}