update some sense warning from -Wconversion

src/class/cdc/cdc_device.c

@@ -229,7 +229,7 @@ void cdcd_init(void)
   {
     cdcd_interface_t* p_cdc = &_cdcd_itf[i];
 
-    p_cdc->wanted_char = -1;
+    p_cdc->wanted_char = (char) -1;
 
     // default line coding is : stop bit = 1, parity = none, data bits = 8
     p_cdc->line_coding.bit_rate  = 115200;

src/class/msc/msc_device.c

@@ -152,7 +152,7 @@ static inline uint16_t rdwr10_get_blocksize(msc_cbw_t const* cbw)
   // invalid block count
   if (block_count == 0) return 0;
 
-  return cbw->total_bytes / block_count;
+  return (uint16_t) (cbw->total_bytes / block_count);
 }
 
 uint8_t rdwr10_validate_cmd(msc_cbw_t const* cbw)