DATV demod: leandvb: fixed possible int to float conversion issues in computation

plugins/channelrx/demoddatv/leansdr/dsp.h

@@ -327,7 +327,7 @@ struct fir_filter : runnable
     {
         for (int i = 0; i < ncoeffs; ++i)
         {
-            float a = 2 * M_PI * f * (i - ncoeffs / 2);
+            float a = 2 * M_PI * f * (i - ncoeffs / 2.0);
             float c = cosf(a), s = sinf(a);
             // TBD Support T=complex
             shifted_coeffs[i].re = coeffs[i] * c;

plugins/channelrx/demoddatv/leansdr/sdr.h

@@ -743,7 +743,7 @@ struct cstln_lut : cstln_base
 
         { // Average power in first quadrant with unit grid
             int q = m / 2;
-            float avgpower = 2 * (q * 0.25 + (q - 1) * q / 2 + (q - 1) * q * (2 * q - 1) / 6) / q;
+            float avgpower = 2 * (q * 0.25 + (q - 1) * q / 2.0 + (q - 1) * q * (2 * q - 1) / 6.0) / q;
             scale = 1.0 / sqrtf(avgpower);
         }
         // Arbitrary mapping