power: supply: bq27xxx: restrict no-battery detection to bq27000

power: supply: bq27xxx: restrict no-battery detection to bq27000

There are fuel gauges in the bq27xxx series (e.g. bq27z561) which may in some
cases report 0xff as the value of BQ27XXX_REG_FLAGS that should not be
interpreted as "no battery" like for a disconnected battery with some built
in bq27000 chip.

So restrict the no-battery detection originally introduced by

    commit 3dd843e1c26a ("bq27000: report missing device better.")

to the bq27000.

There is no need to backport further because this was hidden before

	commit f16d9fb6cf03 ("power: supply: bq27xxx: Retrieve again when busy")

Fixes: f16d9fb6cf03 ("power: supply: bq27xxx: Retrieve again when busy")
Suggested-by: Jerry Lv <Jerry.Lv@axis.com>
Cc: stable@vger.kernel.org
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://lore.kernel.org/r/dd979fa6855fd051ee5117016c58daaa05966e24.1755945297.git.hns@goldelico.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>