vmxnet3: Eliminate __packed redefined warning

This eliminates a warning about __packed being redefined as exposed by the
vmxnet3 code. __packed is not used anywhere in the vmxnet3 code.

  CC    hw/net/vmxnet3.o
In file included from hw/net/vmxnet3.c:29:
hw/net/vmxnet3.h:37:1: warning: "__packed" redefined
In file included from /usr/include/stdlib.h:38,
                 from /buildbot-qemu/default_openbsd_current/build/include/qemu-common.h:26,
                 from /buildbot-qemu/default_openbsd_current/build/include/hw/hw.h:5,
                 from hw/net/vmxnet3.c:18:
/usr/include/sys/cdefs.h:209:1: warning: this is the location of the previous definition

Signed-off-by: Brad Smith <brad@comstyle.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

hw/net/vmxnet3.h

@@ -34,7 +34,6 @@
 #define __le16  uint16_t
 #define __le32  uint32_t
 #define __le64  uint64_t
-#define __packed QEMU_PACKED
 
 #if defined(HOST_WORDS_BIGENDIAN)
 #define __BIG_ENDIAN_BITFIELD
@@ -749,7 +748,6 @@ struct Vmxnet3_DriverShared {
 #undef __le16
 #undef __le32
 #undef __le64
-#undef __packed
 #if defined(HOST_WORDS_BIGENDIAN)
 #undef __BIG_ENDIAN_BITFIELD
 #endif