Rename GPDMA channel disable_force() to disable().

There was nothing particularly forceful about the disable_force() code. Whether it's a "forced" operation depends on what happens before and after (HALT and ACTIVE flags are involved in a smooth disabling of the channel).

firmware/common/gpdma.cpp

@@ -54,7 +54,7 @@ void Channel::configure(
 	const LLI& first_lli,
 	const uint32_t config
 ) const {
-	disable_force();
+	disable();
 	clear_interrupts();
 
 	LPC_GPDMA_Channel_Type* const channel = &LPC_GPDMA->CH[number];

firmware/common/gpdma.hpp

@@ -313,7 +313,7 @@ public:
 		return LPC_GPDMA->CH[number].CONFIG & (1U << 0);
 	}
 
-	void disable_force() const {
+	void disable() const {
 		LPC_GPDMA->CH[number].CONFIG &= ~(1U << 0);
 	}
 
@@ -349,7 +349,7 @@ public:
 
 	void disable() const {
 		for(const auto& channel : channels) {
-			channel.disable_force();
+			channel.disable();
 		}
 		LPC_GPDMA->CONFIG &= ~(1U << 0);
 	}