x86/shadow: adjust 2-level case of SHADOW_FOREACH_L2E()

x86/shadow: adjust 2-level case of SHADOW_FOREACH_L2E()

Coverity apparently takes issue with the assignment inside an if(), but
then only in two of the cases (sh_destroy_l2_shadow() and
sh_unhook_32b_mappings()). As it's pretty simple to break out of the
outer loop without the need for a local helper variable, adjust the code
that way.

While there, with the other "unused value" reports also in mind, further
drop a dead assignment from SHADOW_FOREACH_L1E().

Coverity-ID: 1492857
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>