[Thumb1] The recently added tADCS and tSBCS pseudo-instructions were missing `Uses = [CPSR]`

Summary: Thanks to Oliver Stannard for helping catch this.

Reviewers: olista01, efriedma

Subscribers: llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D31815

llvm-svn: 300951