hw/intc/arm_gic: Switch to read/write callbacks with tx attributes

hw/intc/arm_gic: Switch to read/write callbacks with tx attributes

Switch the GIC's MMIO callback functions to the read_with_attrs
and write_with_attrs functions which provide MemTxAttrs. This will
allow the GIC to correctly handle secure and nonsecure register
accesses.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1430502643-25909-4-git-send-email-peter.maydell@linaro.org