arm: lib: import muldi3.S from Linux

Import muldi3.S from Linux 4.4.6 , commit 0d1912303e54ed1b2a371be0bba51c384dd57326
on arm32. This file implements __aeabi_lmul and it's alias __muldi3, which
is needed when doing Thumb1 builds.

This patch also defines CONFIG_THUMB2_KERNEL and CONFIG_ARM_ASM_UNIFIED
which is necessary for correct build of these files both in ARM and
Thumb mode, just like Linux does.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index de933ab..0e05e87 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -6,7 +6,8 @@
 #
 
 lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o lshrdi3.o \
-				    lib1funcs.o uldivmod.o div0.o div64.o
+				    lib1funcs.o uldivmod.o div0.o \
+				    div64.o muldi3.o
 
 ifdef CONFIG_CPU_V7M
 obj-y	+= vectors_m.o crt0.o