USB: MUSB: save hardware revision at init

MUSB: save hardware revision at init

This can be used later to flag workarounds for issues affecting
particular revisions. Saving this at init avoids having to
read the HWVERS register multiple times in code.

While at it, use macros to extract the version information
instead of using hardcoded values.

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: Ajay Kumar Gupta <ajay.gupta@ti.com>
Acked-by: Felipe Balbi <felipe.balbi@nokia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>