powerpc/32: Get rid of sub_reloc_offset()

sub_reloc_offset() has not been used since commit
917f0af9e5a9 ("powerpc: Remove arch/ppc and include/asm-ppc") which
removed include/asm-ppc/prom.h.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/misc_32.S

@@ -103,20 +103,6 @@ _GLOBAL(mulhdu)
 	addze	r3,r10
 	blr
 
-/*
- * sub_reloc_offset(x) returns x - reloc_offset().
- */
-_GLOBAL(sub_reloc_offset)
-	mflr	r0
-	bl	1f
-1:	mflr	r5
-	lis	r4,1b@ha
-	addi	r4,r4,1b@l
-	subf	r5,r4,r5
-	subf	r3,r5,r3
-	mtlr	r0
-	blr
-
 /*
  * reloc_got2 runs through the .got2 section adding an offset
  * to each entry.