xen/arm: Fix regression after commit d963923

xen/arm: Fix regression after commit d963923

The commit d963923  "xen: arm: correct return value of
raw_copy_{to/from}_guest_*, raw_clear_guest" doesn't permit to boot guest
on Xen ARM.

Remove the stray semicolon from the end of the if statement.

Also we want to get the right rc in the error arrays, so we need to do the
copy_to_guest_offset before checking the rc returned by
xenmem_add_to_physmap_one.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- expanded commit log ]