Fix harmless if statements with empty body, spotted by clang

These clang errors are harmless but worth fixing:
  CC    libhw64/fdc.o
/src/qemu/hw/fdc.c:998:74: error: if statement has empty body [-Wempty-body]
        FLOPPY_DPRINTF("Floppy digital input register: 0x%02x\n", retval);
  CC    libhw64/cuda.o
/src/qemu/hw/cuda.c:320:66: error: if statement has empty body [-Wempty-body]
        CUDA_DPRINTF("read: reg=0x%x val=%02x\n", (int)addr, val);

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/hw/cuda.c b/hw/cuda.c
index 83ae68a..50950d9 100644
--- a/hw/cuda.c
+++ b/hw/cuda.c
@@ -316,8 +316,10 @@
         val = s->anh;
         break;
     }
-    if (addr != 13 || val != 0)
+    if (addr != 13 || val != 0) {
         CUDA_DPRINTF("read: reg=0x%x val=%02x\n", (int)addr, val);
+    }
+
     return val;
 }