misc: hi6421-spmi-pmic: Use generic_handle_irq_safe().

generic_handle_irq() is invoked from a regular interrupt service
routine. This handler will become a forced-threaded handler on
PREEMPT_RT and will be invoked with enabled interrupts. The
generic_handle_irq() must be invoked with disabled interrupts in order
to avoid deadlocks.

Instead of manually disabling interrupts before invoking use
generic_handle_irq_safe() which can be invoked with enabled and disabled
interrupts.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org> 
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220211181500.1856198-5-bigeasy@linutronix.de