arm/vgic: drop const attribute from gic_iomem_deny_access()

arm/vgic: drop const attribute from gic_iomem_deny_access()

While correct from a code point of view, the usage of the const
attribute for the domain parameter of gic_iomem_deny_access() is at
least partially bogus.  Contents of the domain structure (the iomem
rangeset) is modified by the function.  Such modifications succeed
because right now the iomem rangeset is allocated separately from
struct domain, and hence is not subject to the constness of struct
domain.

Amend this by dropping the const attribute from the function
parameter.

This is required by further changes that will convert
iomem_{permit,deny}_access into a function.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>