Remove compiler warnings for gcc 4.5.0

init/main.c:734:10: warning: 'calltime.tv64' may be used uninitialized in
	this function
kernel/async.c:127:10: warning: 'calltime.tv64' may be used uninitialized in
	this function
kernel/async.c:283:10: warning: 'starttime.tv64' may be used uninitialized in
	this function
drivers/base/power/main.c:305:10: warning: 'calltime.tv64' may be used uninitialized
	in this function
drivers/base/power/main.c:305:10: warning: 'calltime.tv64' may be used uninitialized
	in this function
fs/eventpoll.c:1118:7: warning: 'slack' may be used uninitialized in this function
drivers/md/dm.c:1118:3: warning: statement with no effect
drivers/md/dm.c:1146:3: warning: statement with no effect
drivers/md/dm-table.c:1065:2: warning: statement with no effect
drivers/md/dm-table.c:1071:2: warning: statement with no effect
net/ipv4/netfilter/nf_nat_standalone.c:118:2: warning: case value '4' not
	in enumerated type 'enum ip_conntrack_info'
net/netfilter/nf_conntrack_netlink.c:762:11: warning: comparison between
	'enum ctattr_tuple' and 'enum ctattr_type'
lib/decompress_bunzip2.c:511:1: warning: the frame size of 1872 bytes is
	larger than 1024 bytes
drivers/regulator/core.c:2606:17: warning: 'err_ptr' may be used uninitialized
	in this function
drivers/media/video/gspca/gspca.c:1508:2: warning: case value '7' not in
	enumerated type 'enum v4l2_memory'

Change-Id: I72bd4784836c1f18d643b0747a296a2660106fa9
Signed-off-by: Ezra Godfrey <egodfrey@codeaurora.org>