sh: always link in helper functions extracted from libgcc

E.g. landisk_defconfig, which has CONFIG_NTFS_FS=m:

  ERROR: "__ashrdi3" [fs/ntfs/ntfs.ko] undefined!

For "lib-y", if no symbols in a compilation unit are referenced by other
units, the compilation unit will not be included in vmlinux.  This
breaks modules that do reference those symbols.

Use "obj-y" instead to fix this.

http://kisskb.ellerman.id.au/kisskb/buildresult/8838077/

This doesn't fix all cases. There are others, e.g. udivsi3.
This is also not limited to sh, many architectures handle this in the
same way.

A simple solution is to unconditionally include all helper functions.
A more complex solution is to make the choice of "lib-y" or "obj-y" depend
on CONFIG_MODULES:

  obj-$(CONFIG_MODULES) += ...
  lib-y($CONFIG_MODULES) += ...

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Tested-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sh/lib/Makefile

@@ -6,7 +6,7 @@ lib-y  = delay.o memmove.o memchr.o \
 	 checksum.o strlen.o div64.o div64-generic.o
 
 # Extracted from libgcc
-lib-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
+obj-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
 	 ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o \
 	 udiv_qrnnd.o