[stm32] [dma] [irq] Check for pointer first for speed

In case of IRQ for transferComplete is used and halfTransferComplete is
not used:

HT_Flag is always/mostly set when TC_Flag is set.
So checking the flag first is wasting time.

In case that TC_Flag is set and halfTransferComplete is used, IRQ
latency stays the same with this change.

src/modm/platform/dma/stm32/dma.hpp.in

@@ -339,10 +339,12 @@ public:
 				if (transferError)
 					transferError();
 			}
-			if ((isr & HT_Flag) and halfTransferComplete)
+			if (halfTransferComplete and (isr & HT_Flag)) {
 				halfTransferComplete();
-			if ((isr & TC_Flag) and transferComplete)
+			}
+			if (transferComplete and (isr & TC_Flag)) {
 				transferComplete();
+			}
 
 			ControlHal::clearInterruptFlags(InterruptFlags::Global, ChannelID);
 		}