accel/ivpu: Use whole user and shave ranges for preemption buffers

Do not restrict range for preemption buffers allocation just to the end
of user and shave ranges, use them whole instead to avoid situation
where end of range might be already allocated causing preemption buffers
allocation to fail.

Signed-off-by: Karol Wachowski <karol.wachowski@intel.com>
Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240930195322.461209-27-jacek.lawrynowicz@linux.intel.com


Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>