ANDROID: Remove default y on BRIDGE_IGMP_SNOOPING

This binary module gets enabled if BRIDGE, a tristate config, gets
enabled as either a builtin or y. This dependent config should also
be tristate but it seems like that hasn't been done upstream yet.

Bug: 150620456
Test: Treehugger
Signed-off-by: Ram Muthiah <rammuthiah@google.com>
Change-Id: I699b73bfac8a0c6cb5e14fefe56b6c013e2410a8