mlxsw: pci: Make style changes in mlxsw_pci_eq_tasklet()

This function will be used later only for EQ1. As preparation, reorder
variables to reverse xmas tree and return earlier when it is possible, to
simplify the code.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/2412d6c135b2a6aedb4484f5d8baab3aecd7b9ae.1712062203.git.petrm@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>