tMOVCCi pattern only valid for low registers, as the Thumb1 mov immediate to
register instruction only works with low registers. Allowing high registers
for the instruction resulted in the assembler choosing the wide (32-bit)
encoding for the mov, but LLVM though the instruction was only 16 bits wide,
so offset calculations for constant pools became incorrect, leading to
out of range constant pool entries.

llvm-svn: 95686