target: LS1_SAP: fix "declaration of 'read' shadows a global" warning

Change-Id: I7070193819cc134f9fe1427c20a11160ec415ccb
Reported-by: Jens Bauer <jens-lists@gpio.dk>
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/3877
Tested-by: jenkins