tools: Remove -Werror everywhere else

tools: Remove -Werror everywhere else

The previous changeset, e4f5949c4466 ("tools: Add -Werror by default to all
tools/"), added "-Werror" to CFLAGS in tools/Rules.mk.  Remove it from
everywhere else now it is duplicated.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>