Convert

    foo(..., &err);
    if (err) {
        ...
    }

to

    if (!foo(..., &err)) {
        ...
    }

for qdev_realize(), qdev_realize_and_unref(), qbus_realize() and their
wrappers isa_realize_and_unref(), pci_realize_and_unref(),
sysbus_realize(), sysbus_realize_and_unref(), usb_realize_and_unref().
Coccinelle script:

    @@
    identifier fun = {
        isa_realize_and_unref, pci_realize_and_unref, qbus_realize,
        qdev_realize, qdev_realize_and_unref, sysbus_realize,
        sysbus_realize_and_unref, usb_realize_and_unref
    };
    expression list args, args2;
    typedef Error;
    Error *err;
    @@
    -    fun(args, &err, args2);
    -    if (err)
    +    if (!fun(args, &err, args2))
         {
             ...
         }

Chokes on hw/arm/musicpal.c's lcd_refresh() with the unhelpful error
message "no position information".  Nothing to convert there; skipped.

Fails to convert hw/arm/armsse.c, because Coccinelle gets confused by
ARMSSE being used both as typedef and function-like macro there.
Converted manually.

A few line breaks tidied up manually.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200707160613.848843-5-armbru@redhat.com>