CRIS: Drop code related to obsolete or unused kconfigs

Drop all code related to Kconfigs that don't exist.
Fix one Kconfig where it was actually typo:ed (ETRAX_KGB_PORT2)
Drop content related to CRIS v32 SoCs from etraxgpio.h headerfile,
all use of GPIO for both ETRAX FS and ARTPEC-3 should now be through
standard gpiolib instead.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>