hw/ppc/virtex_ml507: Drop use of ppcuic_init()

hw/ppc/virtex_ml507: Drop use of ppcuic_init()

Switch the virtex_ml507 board to directly creating and
configuring the UIC, rather than doing it via the old
ppcuic_init() helper function.

This fixes a trivial Coverity-detected memory leak where
we were leaking the array of IRQs returned by ppcuic_init().

Fixes: Coverity CID 1421992
Signed-off-by: Peter Maydell <[email protected]>
Message-Id: <20201212001537[email protected]>
Reviewed-by: Edgar E. Iglesias <[email protected]>
Tested-by: Edgar E. Iglesias <[email protected]>
Signed-off-by: David Gibson <[email protected]>