Initialization of the IPA driver has several phases:
   - "init" phase can be done without any access to IPA hardware
   - "config" phase requires the IPA hardware to be clocked
   - "setup" phase requires the GSI layer to be functional

Currently, initialization for the IPA interrupt handling code occurs
in the setup phase.  It requires access to the IPA hardware but does
not need GSI, so it can be moved to the config phase instead.

Call the interrupt configuration function early in ipa_config()
rather than from ipa_setup().  Rename ipa_interrupt_setup() to be
ipa_interrupt_config(), and ipa_interrupt_teardown() to be
ipa_interupt_deconfig(), so their names properly indicate when
they get called.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>