rpm-pkg: Fix when current directory is a symlink

The better fix would be to stop using the parent directory (principle of
least surprise), but as long as we use it, use it consistently.

Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/package/Makefile

@@ -28,7 +28,7 @@ RPM := $(shell if [ -x "/usr/bin/rpmbuild" ]; then echo rpmbuild; \
 # Remove hyphens since they have special meaning in RPM filenames
 KERNELPATH := kernel-$(subst -,_,$(KERNELRELEASE))
 MKSPEC     := $(srctree)/scripts/package/mkspec
-PREV       := set -e; cd ..;
+PREV       := set -e; cd -P ..;
 
 # rpm-pkg
 # ---------------------------------------------------------------------------