mfd: altera-sysmgr: Fix device leak on sysmgr regmap lookup

Make sure to drop the reference taken to the sysmgr platform device when
retrieving its driver data.

Note that holding a reference to a device does not prevent its driver
data from going away.

Fixes: f36e789a1f8d ("mfd: altera-sysmgr: Add SOCFPGA System Manager")
Cc: [e-mail] # 5.2
Signed-off-by: Johan Hovold <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/altera-sysmgr.c

···
 
 	sysmgr = dev_get_drvdata(dev);
 
+	put_device(dev);
+
 	return sysmgr->regmap;
 }
 EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_phandle);