libcamera: ipa: Make <ipa/ipa_controls.h> self-contained

The <ipa/ipa_controls.h> header makes use of uint*_t types, but doesn't
include stdint.h. Fix it, and include ipa_controls.h in ipa_controls.cpp
to test compilation of the header on its own.

While at it, fix the comment as the top of ipa_controls.cpp to refer to
the correct file name.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/ipa/ipa_controls.h

@@ -7,6 +7,8 @@
 #ifndef __LIBCAMERA_IPA_CONTROLS_H__
 #define __LIBCAMERA_IPA_CONTROLS_H__
 
+#include <stdint.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif