power/usb: fix USB suspend requests from USB

The USB suspend specification dictates that
only 2 mA may be drawn from a host.

All power supply framework properties are in
units of 10^-6. Thus the correct current
limit to request would be 2000 uA rather than 0.

Fix this in the relevant USB drivers. Also fix
qpnp-charger which currently looks for this 2 uA limit
rather than 2000 uA.

CRs-Fixed: 583273
Change-Id: I491e6180c0f1f2e38b745fe33970fdae70db2e24
Signed-off-by: David Keitel <dkeitel@codeaurora.org>