soc/intel/quark: Add USB PHY initialization

Add register access support using register scripts.
Initialize the USB PHY using register scripts.

TEST=Build and run on Galileo Gen2

Change-Id: I34a8e78eab3c7314ca34343eccc8aeef0622798a
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/14496
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/soc/intel/quark/Kconfig

@@ -26,6 +26,7 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_RAMSTAGE_X86_32
 	select ARCH_ROMSTAGE_X86_32
 	select ARCH_VERSTAGE_X86_32
+	select REG_SCRIPT
 	select SOC_INTEL_COMMON
 	select SOC_SETS_MTRRS
 	select TSC_CONSTANT_RATE