hw/intc/arm_gicv3: fix an extra left-shift when reading IPRIORITYR

hw/intc/arm_gicv3: fix an extra left-shift when reading IPRIORITYR

When either GICD_IPRIORITYR or GICR_IPRIORITYR is read as a 32-bit
register, the post left-shift operator in the for loop causes an
extra shift after the least significant byte has been placed.

The 32-bit value actually returned is therefore the expected value
shifted left by 8 bits.

Signed-off-by: Amol Surati <[email protected]>
Message-id: 20180614054857[email protected]
Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>