[ARM] 4292/1: ns9xxx: Make REGGET consistant with REGSET

This implies that REGGET gets a new parameter "var" to allow to hold the actual
register value in a variable.

Moreover REGGET was broken because it used "field" instead of
"reg ## _ ## field" which proves that there are no callers to fix :-)

Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>