kgdbts: handle thumb2 kernel

In thumb2, functions addresses have the LSB set; ignore it when comparing with
pc or setting breaks.

This fixes the following kgdbts error:

  kgdbts: BP mismatch c0143020 expected c0143021

...and avoids spurious undefined instructions traps due to "off by one"
breakpoint addresses.

Signed-off-by: Vincent Stehlé <v-stehle@ti.com>
Config

Signed-off-by: Vincent Stehlé <v-stehle@ti.com>
Debug! undef instr

Signed-off-by: Vincent Stehlé <v-stehle@ti.com>