GSP: Fix appending of interrupts to the shared memory buffer

The code was previously appending the interrupt to after the end of the
buffer, instead of at the end.

src/core/hle/service/gsp_gpu.cpp

@@ -210,12 +210,12 @@ void SignalInterrupt(InterruptId interrupt_id) {
     }
     for (int thread_id = 0; thread_id < 0x4; ++thread_id) {
         InterruptRelayQueue* interrupt_relay_queue = GetInterruptRelayQueue(thread_id);
-        interrupt_relay_queue->number_interrupts = interrupt_relay_queue->number_interrupts + 1;
-
         u8 next = interrupt_relay_queue->index;
         next += interrupt_relay_queue->number_interrupts;
         next = next % 0x34; // 0x34 is the number of interrupt slots
 
+        interrupt_relay_queue->number_interrupts += 1;
+
         interrupt_relay_queue->slot[next] = interrupt_id;
         interrupt_relay_queue->error_code = 0x0; // No error
 

src/core/hle/service/gsp_gpu.h

@@ -45,21 +45,16 @@ enum class CommandId : u32 {
 
 /// GSP thread interrupt relay queue
 struct InterruptRelayQueue {
-    union {
-        u32 hex;
-
-        // Index of last interrupt in the queue
-        BitField<0,8,u32>   index;
-
-        // Number of interrupts remaining to be processed by the userland code
-        BitField<8,8,u32>   number_interrupts;
-
-        // Error code - zero on success, otherwise an error has occurred
-        BitField<16,8,u32>  error_code;
-    };
-
-    u32 unk0;
-    u32 unk1;
+    // Index of last interrupt in the queue
+    u8 index;
+    // Number of interrupts remaining to be processed by the userland code
+    u8 number_interrupts;
+    // Error code - zero on success, otherwise an error has occurred
+    u8 error_code;
+    u8 padding1;
+
+    u32 missed_PDC0;
+    u32 missed_PDC1;
 
     InterruptId slot[0x34];   ///< Interrupt ID slots
 };