[Sparc] Mark i128 shift libcalls unavailable in 32-bit mode.

[Sparc] Mark i128 shift libcalls unavailable in 32-bit mode.

Recently, llvm wants to emit calls to these functions, while it didn't
seem to be an issue before. Not sure why. Nor do I know why only these
three are important to disable, out of all of the i128 libcalls.

Nevertheless, many other targets have this snippet of code, so, just
copying it to sparc as well, to unbreak things.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280537 91177308-0d34-0410-b5e6-96231b3b80d8