fix hppfs Makefile breakage

Fallout from commit 46d7b522ebf486edbd096965d534cc6465e9e309 ("uml: move
hppfs_kern.c to hppfs.c")

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hppfs/Makefile

@@ -3,7 +3,4 @@
 # Licensed under the GPL
 #
 
-hppfs-objs := hppfs.o
-
-obj-y =
-obj-$(CONFIG_HPPFS) += $(hppfs-objs)
+obj-$(CONFIG_HPPFS) += hppfs.o