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>

hw/omap_i2c.c

@@ -190,8 +190,9 @@ static uint32_t omap_i2c_read(void *opaque, target_phys_addr_t addr)
             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 */

hw/omap_mmc.c

@@ -559,8 +559,9 @@ static void omap_mmc_cover_cb(void *opaque, int line, int level)
     if (!host->cdet_state && level) {
         host->status |= 0x0002;
         omap_mmc_interrupts_update(host);
-        if (host->cdet_wakeup)
-            /* TODO: Assert wake-up */;
+        if (host->cdet_wakeup) {
+            /* TODO: Assert wake-up */
+        }
     }
 
     if (host->cdet_state != level) {

hw/pxa2xx.c

@@ -1877,8 +1877,9 @@ static void pxa2xx_fir_write(void *opaque, target_phys_addr_t addr,
         s->control[0] = value;
         if (!(value & (1 << 4)))			/* RXE */
             s->rx_len = s->rx_start = 0;
-        if (!(value & (1 << 3)))			/* TXE */
-            /* Nop */;
+        if (!(value & (1 << 3))) {                      /* TXE */
+            /* Nop */
+        }
         s->enable = value & 1;				/* ITR */
         if (!s->enable)
             s->status[0] = 0;

hw/soc_dma.c

@@ -192,12 +192,13 @@ static void soc_dma_ch_freq_update(struct dma_s *s)
     if (s->enabled_count)
         /* We completely ignore channel priorities and stuff */
         s->channel_freq = s->soc.freq / s->enabled_count;
-    else
+    else {
         /* TODO: Signal that we want to disable the functional clock and let
          * the platform code decide what to do with it, i.e. check that
          * auto-idle is enabled in the clock controller and if we are stopping
          * the clock, do the same with any parent clocks that had only one
-         * user keeping them on and auto-idle enabled.  */;
+         * user keeping them on and auto-idle enabled.  */
+    }
 }
 
 void soc_dma_set_request(struct soc_dma_ch_s *ch, int level)