usb: PS3 EHCI HC reset work-around

PS3 EHCI HC errata fix 316 - The PS3 EHCI HC will reset its
internal INSNREGXX setup regs back to the chip default values
on Host Controller Reset (CMD_RESET) or Light Host Controller
Reset (CMD_LRESET).  The work-around for this is for the HC
driver to re-initialise these regs when ever the HC is reset.

Adds a new helper routine ps3_ehci_setup_insnreg() which is
called from ps3_ehci_hc_reset().

Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>