backlight: ipaq_micro: Make structure micro_bl_props constant

backlight: ipaq_micro: Make structure micro_bl_props constant

Static structure micro_bl_props, having type backlight_properties, is
used only once, when it is passed as the last argument to function
devm_backlight_device_register(). devm_backlight_device_register() is
defined with its last parameter being declared constant. Hence make
micro_bl_props itself constant as well.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>