The IPA structure contains an ipa_interrupt structure pointer, and
that structure is declared in "ipa.h".  There is no need to include
"ipa_interrupt.h" in that header file.

Instead, include "ipa_interrupt.h" in the three source files (in
addition to "ipa_main.c") that actually use the functions that are
declared there.

Similarly, three files use symbols defined in "ipa_reg.h" but do not
include that file; include it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>