regulator: da9211: Use irq handler when ready

In the Linux kernel, the following vulnerability has been resolved:

regulator: da9211: Use irq handler when ready

If the system does not come from reset (like when it is kexec()), the

regulator might have an IRQ waiting for us.

If we enable the IRQ handler before its structures are ready, we crash.

This patch fixes:

[ 1.141839] Unable to handle kernel read from unreadable memory at virtual address 0000000000000078

[ 1.316096] Call trace:

[ 1.316101] blocking_notifier_call_chain+0x20/0xa8

[ 1.322757] cpu cpu0: dummy supplies not allowed for exclusive requests

[ 1.327823] regulator_notifier_call_chain+0x1c/0x2c

[ 1.327825] da9211_irq_handler+0x68/0xf8

[ 1.327829] irq_thread+0x11c/0x234

[ 1.327833] kthread+0x13c/0x154