rx: Rename QOM type check macros

rx: Rename QOM type check macros

Currently we have a RXCPU typedef and a RXCPU type checking
macro, but OBJECT_DECLARE* would transform the RXCPU macro into a
function, and the function name would conflict with the typedef
name.

Rename the RXCPU* QOM type check macros to RX_CPU*, so we will
avoid the conflict and make the macro names consistent with the
TYPE_RX_CPU constant name.

This will make future conversion to OBJECT_DECLARE* easier.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200825192110.3528606-53-ehabkost@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>