sc53c94: Move DATA_FIFO_MAX from header.

Headers shouldn't make defines that are not meant to be used outside the source file.

devices/common/scsi/sc53c94.cpp

@@ -376,6 +376,8 @@ void Sc53C94::exec_next_command()
     }
 }
 
+#define DATA_FIFO_MAX   16
+
 void Sc53C94::fifo_push(const uint8_t data)
 {
     if (this->data_fifo_pos < DATA_FIFO_MAX) {

devices/common/scsi/sc53c94.h

@@ -38,8 +38,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 class DmaBidirChannel;
 class InterruptCtrl;
 
-#define DATA_FIFO_MAX   16
-
 /** 53C94 read registers */
 namespace Read {
     enum Reg53C94 : uint8_t {