rules.mk: correct BUILD_PATH to allow build irrespective of format
Created by: uarif1
Without this patch, the BUILD_PATH cannot end with a /. With this patch, the end of BUILD_PATH does not matter. BUILD_PATH can be automatically generated by build systems, so it is important that any format is supported.
Change-Id: Iba306f8ac29a528fa6a7dc0a37e3c3b7ef7d0309 Signed-off-by: Usama Arif usama.arif@arm.com