MathUtil: Convert Clamp into a constexpr function

Source/Core/Core/HW/StreamADPCM.cpp

@@ -31,8 +31,7 @@ static s16 ADPDecodeSample(s32 bits, s32 q, s32& hist1, s32& hist2)
 		hist = (hist1 * 0x62) - (hist2 * 0x37);
 		break;
 	}
-	hist = (hist + 0x20) >> 6;
-	MathUtil::Clamp(&hist, -0x200000, 0x1fffff);
+	hist = MathUtil::Clamp((hist + 0x20) >> 6, -0x200000, 0x1fffff);
 
 	s32 cur = (((s16)(bits << 12) >> (q & 0xf)) << 6) + hist;
 
@@ -40,7 +39,7 @@ static s16 ADPDecodeSample(s32 bits, s32 q, s32& hist1, s32& hist2)
 	hist1 = cur;
 
 	cur >>= 6;
-	MathUtil::Clamp(&cur, -0x8000, 0x7fff);
+	cur = MathUtil::Clamp(cur, -0x8000, 0x7fff);
 
 	return (s16)cur;
 }