stm32mp1: update device tree and gpio functions

stm32mp1: update device tree and gpio functions

Change fdt_check_status function to fdt_get_status.
Update GPIO defines.
Move some functions in gpio driver, instead of dt helper file.
Add GPIO bank helper functions.
Use only one status field in dt_node_info structure including both status
and secure status.

Change-Id: I34f93408dd4aac16ae722f564bc3f7d6ae978cf4
Signed-off-by: Yann Gautier <[email protected]>
Signed-off-by: Etienne Carriere <[email protected]>
Signed-off-by: Lionel Debieve <[email protected]>
Signed-off-by: Nicolas Le Bayon <[email protected]>