armv8: lx2160a: Add FSL_PEX_STREAM_ID_END for LX2160A

Add FSL_PEX_STREAM_ID_END and remove FSL_PEX_STREAM_ID_NUM
for lx2160a.

Signed-off-by: Wasim Khan <wasim.khan@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>