libcamera: base: timer: Drop start() overload with int argument

The start(unsigned int msec) overload is error-prone, as the argument
unit can easily be mistaken in callers. Drop it and update all callers
to use the start(std::chrono::milliseconds) overload instead.

The callers now need to use std::chrono_literals. The using statement
could be added to timer.h for convenience, but "using" is discouraged in
header files to avoid namespace pollution. Update the callers instead,
and while at it, sort the "using" statements alphabetically in tests.

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

test/ipc/unixsocket.cpp

@@ -30,8 +30,9 @@
 #define CMD_LEN_CMP	3
 #define CMD_JOIN	4
 
-using namespace std;
 using namespace libcamera;
+using namespace std;
+using namespace std::chrono_literals;
 
 int calculateLength(int fd)
 {
@@ -430,7 +431,7 @@ private:
 		if (ret)
 			return ret;
 
-		timeout.start(200);
+		timeout.start(200ms);
 		while (!callDone_) {
 			if (!timeout.isRunning()) {
 				cerr << "Call timeout!" << endl;