library: miscellaneous minor accumulated <pids> tweaks

library: miscellaneous minor accumulated <pids> tweaks

This patch contains the following minor modifications:

. When assigning to boot_seconds from a double, a cast
to 'unsigned long' was employed that in reality should
have been 'unsigned long long'. But, on second thought
it's probably best if the compiler makes the decision.

. Results for ID_TGID do not require an 'f_status' flg
since both tid and tgid will be available by virtue of
the 'simple_nextpid' function normal operations. Thus,
that flag has been removed from the <pids> Item_table.

. When the pids_stacks structure was eliminated with a
change to the alloc/dealloc functions in the reference
below, several casts became redundant and are removed.

Reference(s):
commit 747dfc5987e6e91ea3a8575de307e2892790c598.

Signed-off-by: Jim Warner <james.warner@comcast.net>