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>

Import ctzdi2.c from LLVM compiler-rt ...

When using __builtin_ctzll() in AArch32 code, the compiler may translate
that into a call to the __ctzdi2() function. In this case, the linking
phase fails because TF doesn't provide an implementation for it.

This patch imports the implementation of the __ctzdi2() function from
LLVM's compiler-rt project and hooks it into TF's build system. The
ctzdi2.c file is an unmodified copy from the master branch as of
July 19 2017 (SVN revision: 308480).

Change-Id: I96766a025ba28e1afc6ef6a5c4ef91d85fc8f32b
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

Hook up LLVM compiler-rt in the build system ...

This patch enables compiler-rt for the AArch32 target.  The code is
not used for AArch64 as the architecture supports the 64-bit division
and modulo operations natively.

Change-Id: I1703a92872b0bb56ac0b98c67193830683963b13
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>