libxc: fixes for the ARM platform

libxc: fixes for the ARM platform

Make xc_dom_feature_translated an arch-dependent function.

alloc_magic_pages: save console and xenstore pfn's in xc_dom_image.
alloc_magic_pages: set HVM_PARAM_CONSOLE_EVTCHN and
HVM_PARAM_STORE_EVTCHN hvm_params using the event channels allocated by
the toolstack.

Call xc_dom_gnttab_hvm_seed instead of xc_dom_gnttab_seed in
xc_dom_gnttab_init for autotranslated guests.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>