various: Remove unnecessary OBJECT() cast

The OBJECT() macro is defined as:

  #define OBJECT(obj) ((Object *)(obj))

Remove the unnecessary OBJECT() casts when we already know the
pointer is of Object type.

Patch created mechanically using spatch with this script:

  @@
  typedef Object;
  Object *o;
  @@
  -   OBJECT(o)
  +   o

Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: John Snow <jsnow@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200512070020.22782-3-f4bug@amsat.org>
[Trivial rebase conflict in hw/s390x/sclp.c resolved]
diff --git a/hw/ipmi/smbus_ipmi.c b/hw/ipmi/smbus_ipmi.c
index 2a9470d..f1a0148 100644
--- a/hw/ipmi/smbus_ipmi.c
+++ b/hw/ipmi/smbus_ipmi.c
@@ -329,7 +329,7 @@
 {
     SMBusIPMIDevice *sid = SMBUS_IPMI(obj);
 
-    ipmi_bmc_find_and_link(OBJECT(obj), (Object **) &sid->bmc);
+    ipmi_bmc_find_and_link(obj, (Object **) &sid->bmc);
 }
 
 static void smbus_ipmi_get_fwinfo(struct IPMIInterface *ii, IPMIFwInfo *info)