ab8500-btemp: Adaptation to AB8505 and AB9540 platforms

Add AB9540 and AB8505 support to ABx500 BTEMP driver.

Signed-off-by: Rajkumar Kasirajan <rajkumar.kasirajan@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Michel JAOUEN <michel.jaouen@stericsson.com>
Reviewed-by: Marcus COOPER <marcus.xm.cooper@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Tested-by: Michel JAOUEN <michel.jaouen@stericsson.com>
Tested-by: Jonas ABERG <jonas.aberg@stericsson.com>