HLE: Fix some type convert warnings.

Almost missed these.

Core/HLE/sceMp4.cpp

@@ -252,7 +252,7 @@ static u32 sceAacInit(u32 id)
 
 	aac->Channels = 2;
 	aac->MaxOutputSample = aac->PCMBufSize / 4;
-	aac->SetReadPos(aac->startPos);
+	aac->SetReadPos((int)aac->startPos);
 	aac->audioType = PSP_CODEC_AAC;
 
 	// create aac decoder

Core/HLE/scePower.cpp

@@ -81,7 +81,7 @@ int PowerCpuMhzToHz(int desired, int pllHz) {
 	}
 
 	// We match the PSP's HLE funcs better when we have the same float error, it seems.
-	return (float)(freq / 1000000.0f) * 1000000;
+	return (int)((float)(freq / 1000000.0f) * 1000000);
 }
 
 int PowerPllMhzToHz(int mhz) {