add additional symbols to xen-syms.map

add additional symbols to xen-syms.map

Add "all_symbols" to all /tools/symbols calls so that
xen-syms.map lists all symbols and not only .text section
symbols. This change enhances debugging and livepatch
capabilities.

Signed-off-by: Michael Kurth <mku@amazon.de>
Reviewed-by: Eslam Elnikety <elnikety@amazon.de>
Reviewed-by: Julien Grall <jgrall@amazon.co.uk>
Reviewed-by: Robert Stonehouse <rjstone@amazon.co.uk>
Reviewed-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Acked-by: Jan Beulich <jbeulich@suse.com>