Fix assert in RegisterValue::SetBytes if we're trying to
write a 32-byte value into a 32-byte ymm vector reg - that 
is allowed.
<rdar://problem/13350587> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@176740 91177308-0d34-0410-b5e6-96231b3b80d8