remoteproc: qcom: pas: Fix the PAS context creation placement

DTB PAS context creation should be done only for subsystems that support
a DTB firmware binary; otherwise, memory is wasted. Move the context
creation to the appropriate location.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260724182858.1868271-4-mukesh.ojha@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>