RISC-V: Remove udivdi3

This should never have landed in the first place: it was added as part
of 64-bit divide support for 32-bit systems, but the kernel doesn't
allow this sort of division.  I must have forgotten to remove it.

This patch removes the support.  Since this routine only worked on
64-bit platforms but was only built on 32-bit platforms, it's
essentially just nonsense anyway.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Link: https://lore.kernel.org/linux-riscv/nycvar.YSQ.7.76.1908061413360.19480@knanqh.ubzr/T/#t
Reported-by: Eric Lin <tesheng@andestech.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

arch/riscv/lib/Makefile

@@ -5,5 +5,3 @@ lib-y	+= memset.o
 lib-y	+= uaccess.o
 
 lib-$(CONFIG_64BIT) += tishift.o
-
-lib-$(CONFIG_32BIT) += udivdi3.o

arch/riscv/lib/udivdi3.S

@@ -1,32 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2016-2017 Free Software Foundation, Inc.
- */
-
-#include <linux/linkage.h>
-
-ENTRY(__udivdi3)
-	mv	a2, a1
-	mv	a1, a0
-	li	a0, -1
-	beqz	a2, .L5
-	li	a3, 1
-	bgeu	a2, a1, .L2
-.L1:
-	blez	a2, .L2
-	slli	a2, a2, 1
-	slli	a3, a3, 1
-	bgtu	a1, a2, .L1
-.L2:
-	li	a0, 0
-.L3:
-	bltu	a1, a2, .L4
-	sub	a1, a1, a2
-	or	a0, a0, a3
-.L4:
-	srli	a3, a3, 1
-	srli	a2, a2, 1
-	bnez	a3, .L3
-.L5:
-	ret
-ENDPROC(__udivdi3)