power: qpnp-smb2: Specify interrupt flags

Specify the IRQ flags while registering the charger
interrupts. Required for the interrupts to be setup with the
right type.

CRs-Fixed: 2076000
Change-Id: I3db875150a4b53df2acdd3c4ee385c1b22f05be1
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>