libcamera: Standardise on C compatibility headers

Now that our usage of C compatibility header is documented, use them
consistently through the source code.

While at it, group the C and C++ include statements as defined in the
coding style, and fix a handful of #include ordering issues.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/ipa/rkisp1/rkisp1.cpp

@@ -6,9 +6,9 @@
  */
 
 #include <algorithm>
-#include <cstdint>
 #include <math.h>
 #include <queue>
+#include <stdint.h>
 #include <string.h>
 
 #include <linux/rkisp1-config.h>