mhi: core: do not process sys_error if rddm mode is supported

Device that support RDDM do not require processing SYS_ERROR since
it's redundant. This change avoid processing sys error if rddm
is supported by the device.

CRs-Fixed: 2495678
Change-Id: I47ca39bda7b5b17e16ae62aa44a0d9bdb93e650d
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>