driver: net: fsl-mc: Return from DPAA_exit if boot_status !=0

Return value of get_mc_boot_status() in case of failure is not necessary
to be -1.

So update the error condition check.

Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Reported-by: Yao Yuan <yao.yuan@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: York Sun <york.sun@nxp.com>