OMAP2+: hwmod: use status bit info for reset line

On OMAP2 and OMAP3 the reset ctrl shift doesn't match the
status bit, as it does on OMAP4, when handling the reset lines.

This patch adds a new member in the reset info structure, so now it
can be added as part of hwmod data, and checked accordingly for
OMAP2 or 3; otherwise, there could be cases when the shift masks
doesn't match both of the registers, and a successful reset might
throw an error message or vice versa.

Signed-off-by: Omar Ramirez Luna <omar.ramirez@ti.com>
[paul@pwsan.com: added a warning if st_shift used on OMAP4; renamed 'r'
 variable; improved some documentation]
Signed-off-by: Paul Walmsley <paul@pwsan.com>