compiler_rt: Import lshrdi3.c file

Imported from the LLVM compiler_rt library on master branch as of
30 Oct 2018 (SVN revision: r345645).

This is to get the __aeabi_llsr() builtin, which is required by a
subsequent patch that uses a logical right shift operator in AArch32.

Change-Id: I9884139a12855a8a87206fb572aaa7dd35582b09
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/lib/compiler-rt/compiler-rt.mk b/lib/compiler-rt/compiler-rt.mk
index cb5ab31..49e497e 100644
--- a/lib/compiler-rt/compiler-rt.mk
+++ b/lib/compiler-rt/compiler-rt.mk
@@ -31,5 +31,6 @@
 ifeq (${ARCH},aarch32)
 COMPILER_RT_SRCS	:=	lib/compiler-rt/builtins/arm/aeabi_uldivmod.S	\
 				lib/compiler-rt/builtins/udivmoddi4.c		\
-				lib/compiler-rt/builtins/ctzdi2.c
+				lib/compiler-rt/builtins/ctzdi2.c		\
+				lib/compiler-rt/builtins/lshrdi3.c
 endif