Revert "[llvm][CodeGen] Addressing modes for SVE stN."

Revert "[llvm][CodeGen] Addressing modes for SVE stN."

This reverts commit fc4e954ed5c0825cdfe3a590ff1904ef38bc47db.

The commit reported the following failure:

http://lab.llvm.org:8011/builders/clang-armv7-linux-build-cache/builds/29420

FAILED: lib/Target/AArch64/CMakeFiles/LLVMAArch64CodeGen.dir/AArch64ISelDAGToDAG.cpp.o
/usr/bin/c++   -DGTEST_HAS_RTTI=0 -D_DEBUG -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib/Target/AArch64 -I/home/buildslave/buildslave/clang-armv7-linux-build-cache/llvm/llvm/lib/Target/AArch64 -I/usr/include/libxml2 -Iinclude -I/home/buildslave/buildslave/clang-armv7-linux-build-cache/llvm/llvm/include -mthumb -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wstring-conversion -fdiagnostics-color -ffunction-sections -fdata-sections -O3  -fvisibility=hidden    -fno-exceptions -fno-rtti -UNDEBUG -std=c++14 -MMD -MT lib/Target/AArch64/CMakeFiles/LLVMAArch64CodeGen.dir/AArch64ISelDAGToDAG.cpp.o -MF lib/Target/AArch64/CMakeFiles/LLVMAArch64CodeGen.dir/AArch64ISelDAGToDAG.cpp.o.d -o lib/Target/AArch64/CMakeFiles/LLVMAArch64CodeGen.dir/AArch64ISelDAGToDAG.cpp.o -c /home/buildslave/buildslave/clang-armv7-linux-build-cache/llvm/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
/home/buildslave/buildslave/clang-armv7-linux-build-cache/llvm/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp:1439:10: error: chosen constructor is explicit in copy-initialization
  return {IsRegReg ? Opc_rr : Opc_ri, NewBase, NewOffset};
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	   /usr/bin/../lib/gcc/arm-linux-gnueabihf/5.4.0/../../../../include/c++/5.4.0/tuple:479:19: note: explicit constructor declared here
	           constexpr tuple(_UElements&&... __elements)