lis3: add power management functions

This enabled power management functions for the SPI transport layer of the
lis3 devices.  The device's suspend mode is only entered in case no wakeup
threshold has been given.  In this case, the device is supposed to wake up
the system and must thus not be put to deep sleep.

[randy.dunlap@oracle.com: fix lis3-spi for CONFIG_PM=n]
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>