[PowerPC] Remove old README.txt entry regarding struct passing

Because of how Clang represents structs as arrays (at least on non-Darwin
platforms), and what SROA does, etc. this is no longer a problem.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225251 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed