Use gcc warning flag -Wempty-body

If the compiler supports the warning flag -Wempty-body, use it.

Adjust the code to avoid the warnings.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/hw/omap_i2c.c b/hw/omap_i2c.c
index d7c1888..d133977 100644
--- a/hw/omap_i2c.c
+++ b/hw/omap_i2c.c
@@ -190,8 +190,9 @@
             if (s->rxlen > 2)
                 s->fifo >>= 16;
             s->rxlen -= 2;
-        } else
-            /* XXX: remote access (qualifier) error - what's that?  */;
+        } else {
+            /* XXX: remote access (qualifier) error - what's that?  */
+        }
         if (!s->rxlen) {
             s->stat &= ~(1 << 3);				/* RRDY */
             if (((s->control >> 10) & 1) &&			/* MST */