numa: show hex number in error message for consistency and prefix them with 0x

numa: show hex number in error message for consistency and prefix them with 0x

The error messages before and after patch are:

before:
qemu-system-x86_64: total memory for NUMA nodes (134217728) should equal RAM size (20000000)

after:
qemu-system-x86_64: total memory for NUMA nodes (0x8000000) should equal RAM size (0x20000000)

Cc: qemu-stable@nongnu.org
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>