net, lib: kill arch_fast_hash library bits

As there are now no remaining users of arch_fast_hash(), lets kill
it entirely.

This basically reverts commit 71ae8aac3e19 ("lib: introduce arch
optimized hash library") and follow-up work, that is f.e., commit
237217546d44 ("lib: hash: follow-up fixups for arch hash"),
commit e3fec2f74f7f ("lib: Add missing arch generic-y entries for
asm-generic/hash.h") and last but not least commit 6a02652df511
("perf tools: Fix include for non x86 architectures").

Cc: Francesco Fusco <fusco@ntop.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index db92793..1530afb 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -23,7 +23,7 @@
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
 
-obj-y += msr.o msr-reg.o msr-reg-export.o hash.o
+obj-y += msr.o msr-reg.o msr-reg-export.o
 
 ifeq ($(CONFIG_X86_32),y)
         obj-y += atomic64_32.o