kgdbts: handle thumb2 kernel

In thumb2, symbols have the LSB set but the actual PC value does not reflect
that. Handle it when comparing symbols addresses to pc.

This fixes the following kgdbts error:

  kgdbts: BP mismatch c0143020 expected c0143021

Signed-off-by: Vincent Stehlé <v-stehle@ti.com>
fixup! Debug! undef instr
fixup! Debug! undef instr
squash! kgdbts: handle thumb2 kernel

Remove lsb when setting breaks