regulator: spm-regulator: correct range name printing

Correct the condition that is checked to determine if an
spm-regulator device is operating in LV (low voltage) or MV
(medium voltage) range.  This ensures that the proper range
name is printed by the probe function.

Change-Id: Ie0e1075405cadd1961beefeef8fb0a8b9c2a6bf4
Signed-off-by: David Collins <collinsd@codeaurora.org>