bf60x: sec: Clean up interrupt initialization code for SEC.

Turn SEC related macro CONFIG_BF60x into SEC_GCTL.
Move machine specific GPIO_PINT macros to machine gpio header.
Split SEC init_arch_irq() and vec_to_irq() from old SIC.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>