Summary: Get rid of the NGROUPS hard limit.

This patch removes all fixed-size arrays which depend on NGROUPS, and
replaces them with struct group_info, which is refcounted, and holds an
array of pages in which to store groups.  groups_alloc() and groups_free()
are used to allocate and free struct group_info, and set_group_info is used
to actually put a group_info into a task.  Groups are sorted and b-searched
for efficiency.  Because groups are stored in a 2-D array, the GRP_AT()
macro was added to allow simple 1-D style indexing.

This patch touches all the compat code in the 64-bit architectures.
These files have a LOT of duplicated code from uid16.c.  I did not try to
reduce duplicated code, and instead followed suit.  A proper cleanup of
those architectures code-bases would be fun.  Any sysconf() which used to
return NGROUPS now returns INT_MAX - there is no hard limit.

This patch also touches nfsd by imposing a limit on the number of groups in
an svc_cred struct.

This patch modifies /proc/pid/status to only display the first 32 groups.

This patch removes the NGROUPS define from all architectures as well as
NGROUPS_MAX.

This patch changes the security API to check a struct group_info, rather
than an array of gid_t.

This patch totally horks Intermezzo.

This was built and tested against 2.6.0-test6 (BK today) on an i386.