arch/arm: let map_mmio_regions() use start and count

arch/arm: let map_mmio_regions() use start and count

Currently, the arguments given to the function map_mmio_regions() to
describe the memory range to be mapped are the start and end page frame
numbers of the range to be mapped. However, this could give rise to
issues due to the range being inclusive or exclusive of the end gfn
given as parameter. This commit changes the interface of the function
to accept the start gfn and the number of gfns to be mapped.
This commit also changes the interface of the function map_one_mmio(),
helper for the xgene-storm platform, which is a wrapper for the function
map_mmio_regions() and does not need its arguments to be paddr_t.

NOTE: platform-specific code has not been tested, save for the
      sunxi and the Arndale Exynos 5 platforms (see the Tested-by
      below for the latter).

Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Tested-by: Julien Grall <julien.grall@citrix.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Paolo Valente <paolo.valente@unimore.it>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Eric Trudeau <etrudeau@broadcom.com>
Cc: Viktor Kleinik <viktor.kleinik@globallogic.com>
[ ijc -- remove stray extra parameter in xgene-storm.c ]