drivers: usb: fsl: Move USB Errata checking code

Move USB Errata checking code from "arch/powerpc" to architecture independent
file "fsl_usb.h" so that errata(s) become independent of the architecture.
For each erratum checking function for PPC arch, define a nop function for
non PPC arch for successful compilation in either case

Signed-off-by: Nikhil Badola <nikhil.badola@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>