coresight: Fixing wrong #ifdef/#endif placement

Fixing problem reported by:
        https://lkml.org/lkml/2015/1/6/86



The #ifdef/#endif is wrong and prevents the stub of function
of_get_coresight_platform_data() from being visible when
CONFIG_OF is not defined.

Moving CONFIG_OF condition out of CONFIG_CORESIGHT, making
them both independent.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>