ARM: fix lcd power build failure in collie_defconfig

Commit 086ada54

  "FB: sa1100: remove global sa1100fb_.*_power function pointers"

got rid of all instances but one in locomolcd.c -- which was
conditional on CONFIG_SA1100_COLLIE.  The associated .power
field which replaces the global is populated in mach-sa1100/collie.c
so move the assignment there, but make it conditional on the
locomolcd support, so use CONFIG_BACKLIGHT_LOCOMO in that file.

Cc: arm@kernel.org
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Olof Johansson <olof@lixom.net>