agm_pcm_plugin: Cast `agm_media_format` to `pcm_format` manually

Signed-off-by: Shinjo Akane <akane@akanework.org>
diff --git a/plugins/tinyalsa/src/agm_pcm_plugin.c b/plugins/tinyalsa/src/agm_pcm_plugin.c
index a0c1864..25343c3 100644
--- a/plugins/tinyalsa/src/agm_pcm_plugin.c
+++ b/plugins/tinyalsa/src/agm_pcm_plugin.c
@@ -219,14 +219,14 @@
         unsigned int frames)
 {
     return frames * config->channels *
-        (agm_format_to_bits(config->format) >> 3);
+        (agm_format_to_bits((enum pcm_format)config->format) >> 3);
 }
 
 static unsigned int agm_pcm_bytes_to_frames(unsigned int bytes,
         struct agm_media_config *config)
 {
     unsigned int frame_bits = config->channels *
-        agm_format_to_bits(config->format);
+        agm_format_to_bits((enum pcm_format)config->format);
 
     return bytes * 8 / frame_bits;
 }
@@ -558,7 +558,7 @@
 
     buff = x->buf;
     count = x->frames * (priv->media_config->channels *
-            agm_format_to_bits(priv->media_config->format) / 8);
+            agm_format_to_bits((enum pcm_format)priv->media_config->format) / 8);
 
     ret = agm_session_write(handle, buff, &count);
     errno = ret;
@@ -580,7 +580,7 @@
 
     buff = x->buf;
     count = x->frames * (priv->media_config->channels *
-            agm_format_to_bits(priv->media_config->format) / 8);
+            agm_format_to_bits((enum pcm_format)priv->media_config->format) / 8);
     ret = agm_session_read(handle, buff, &count);
     errno = ret;