net/net.c: cosmetic: fix indentation

This removes the following checkpatch issues:
 - ERROR: switch and case should be at the same indent
 - WARNING: suspect code indent for conditional statements
 - WARNING: labels should not be indented

Signed-off-by: Luca Ceresoli <luca.ceresoli@comelit.it>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Ben Warren <biggerbadderben@gmail.com>