build: fix dependency tracking for preprocessed files

build: fix dependency tracking for preprocessed files

While the issue is more general, I noticed that asm-macros.i not getting
re-generated as needed. This was due to its .*.d file mentioning
asm-macros.o instead of asm-macros.i. Use -MQ here as well, and while at
it also use -MQ to avoid the somewhat fragile sed-ary on the *.lds
dependency tracking files. While there, further avoid open-coding $(CPP)
and drop the bogus (Arm) / stale (x86) -Ui386.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Paul Durrant <paul@xen.org>