remoteproc: k3-r5: remove sysfw PM calls if not supported

With the sysfw rearch, sysfw PM calls are no longer available from SPL
level. To properly support this, remove the is_on checks and the reset
assertion from the R5 remoteproc driver as these are not supported.
Attempting to access unavailable services will cause the device to hang.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tero Kristo <kristo@kernel.org>