irqchip: gic-v3: Declare rdist as __percpu pointer to __iomem pointer

The __percpu __iomem annotations on the rdist base are contradictory
and confuse static checkers such as sparse.

This patch fixes the anotations so that rdist is described as a __percpu
pointer to an __iomem pointer.

Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1409062410-25891-9-git-send-email-will.deacon@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>