Audio: MFCC: Fix testbench xt build fail

Build with "scripts/rebuild-testbench -p tgl" fails to error:

src/audio/mfcc/mfcc_hifi3.c: In function ‘mfcc_source_copy_s16’:
src/audio/mfcc/mfcc_hifi3.c:91: warning:
assignment from incompatible pointer type

src/audio/mfcc/mfcc_hifi3.c: In function ‘mfcc_fill_prev_samples’:
src/audio/mfcc/mfcc_hifi3.c:124: warning:
assignment from incompatible pointer type

src/audio/mfcc/mfcc_hifi3.c: In function ‘mfcc_fill_fft_buffer’:
src/audio/mfcc/mfcc_hifi3.c:159: warning:
assignment from incompatible pointer type

fixes: d0cb478 ("Audio: MFCC: Add HiFi3 implementation of MFCC")

Signed-off-by: Seppo Ingalsuo <[email protected]>

src/audio/mfcc/mfcc_hifi3.c

@@ -88,7 +88,7 @@ void mfcc_source_copy_s16(struct input_stream_buffer *bsource, struct mfcc_buffe
 	}
 	buf->s_avail += copied;
 	buf->s_free -= copied;
-	buf->w_ptr = out;
+	buf->w_ptr = (int16_t *)out;
 }
 
 void mfcc_fill_prev_samples(struct mfcc_buffer *buf, int16_t *prev_data,
@@ -121,7 +121,7 @@ void mfcc_fill_prev_samples(struct mfcc_buffer *buf, int16_t *prev_data,
 
 	buf->s_avail -= prev_data_length;
 	buf->s_free += prev_data_length;
-	buf->r_ptr = in;
+	buf->r_ptr = (void *)in; /* int16_t pointer but direct cast is not possible */
 }
 
 void mfcc_fill_fft_buffer(struct mfcc_state *state)
@@ -156,7 +156,7 @@ void mfcc_fill_fft_buffer(struct mfcc_state *state)
 
 	buf->s_avail -= fft->fft_hop_size;
 	buf->s_free += fft->fft_hop_size;
-	buf->r_ptr = in;
+	buf->r_ptr = (int16_t *)in;
 
 	/* Copy for next time data back to overlap buffer */
 	idx = fft->fft_fill_start_idx + fft->fft_hop_size;