usb: xhci: Fix suspend/resume when used with OTG core

In the OTG case, the controller might not yet have been
added or is removed before the system suspends.

Assign xhci->main_hcd during probe to prevent NULL
pointer de-reference in xhci_suspend/resume().

Use the hcd->state flag to check if HCD is halted
and if that is so do nothing for xhci_suspend/resume().

[Only for xhci-plat devices, pci devices need it in gen_setup -Mathias]
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 9fa733f24bb54dd532b5f5d7abc275c4a547c69f
Git-repo: git://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git


[mrana@codeaurora.org: Fix minor merge conflict]
Change-Id: If064778fa56a8e41ebfd80884802b2abced514ca
Signed-off-by: Mayank Rana <mrana@codeaurora.org>