[X86] Remove mergeSPUpdatesUp()

X86FrameLowering has both a mergeSPUpdates() that accepts a direction, and an
mergeSPUpdatesUp(), which seem to do the same thing, except for a slightly 
different interface. Removed the less general function.
NFC.

Differential Revision: http://reviews.llvm.org/D11510

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243396 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed