refactor: make silk_LPC_inverse_pred_gain_c and inner LPC_inverse_pred_gain_QA_c safe

Author: DCNick3

src/silk/LPC_fit.rs

@@ -35,7 +35,7 @@ pub fn silk_LPC_fit(a_QOUT: &mut [i16], a_QIN: &mut [i32], QOUT: i32, QIN: i32)
         if maxabs > i16::MAX as i32 {
             /* Reduce magnitude of prediction coefficients */
             maxabs = std::cmp::min(maxabs, 163838); /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */
-            let chirp_Q16 = SILK_FIX_CONST(0.999f64, 16)
+            let chirp_Q16 = SILK_FIX_CONST!(0.999f64, 16)
                 - ((maxabs - i16::MAX as i32) << 14) / ((maxabs * (idx as i32 + 1)) >> 2);
             silk_bwexpander_32(a_QIN, chirp_Q16);
         } else {