MFD: TWL6030: Implementation of the ProDB00110684 errata

This errata affects only TWL6030 ES2.1. Each time a charge is
enabled via SW, a THMREG interrupt triggers (Internal USB charger
fault interrupt line).

Workaround: Interrupt (the bit #1 of CHARGERUSB_INT_MASK) has to be
masked before enabling the charge, and unmasked after charge is
enabled.

Change-Id: I14074e384a863c82ba61af9ea9434afe75cc2bc8
Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@ti.com>