bridge: fdb show: fix fdb entry state output for json context

bridge: fdb show: fix fdb entry state output for json context

bridge json fdb show is printing an incorrect / non-machine readable
value, when using -j (json output) we are expecting machine readable
data that shouldn't require special handling/parsing.

$ bridge -j fdb show | \
python -c \
'import sys,json;print(json.dumps(json.loads(sys.stdin.read()),indent=4))'
[
    {
	"master": "br0",
	"mac": "56:23:28:4f:4f:e5",
	"flags": [],
	"ifname": "vx0",
	"state": "state=0x80"  <<<<<<<<< with the patch: "state": "0x80"
    }
]

Fixes: c7c1a1ef51aea7c ("bridge: colorize output and use JSON print library")
Signed-off-by: Julien Fortin <julien@cumulusnetworks.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>