soc: mediatek: mtk-svs: Enable the IRQ later

soc: mediatek: mtk-svs: Enable the IRQ later

[ Upstream commit edf1e5ab6afe1608af3f1be590ce4b60df84cef5 ]

If the system does not come from reset (like when is booted via
kexec()), the peripheral might triger an IRQ before the data structures
are initialised.

Fixes:

[    0.227710] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000f08
[    0.227913] Call trace:
[    0.227918]  svs_isr+0x8c/0x538

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20221127-mtk-svs-v2-0-145b07663ea8@chromium.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>