soc/apollolake: Add helper functions to access Power Management Registers

Change-Id: I928efea33030e03cbbaead6812c617d20446f7c9
Signed-off-by: Hannah Williams <hannah.williams@intel.com>
Reviewed-on: https://review.coreboot.org/14289
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/soc/intel/apollolake/Makefile.inc

@@ -26,8 +26,10 @@ romstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 romstage-y += memmap.c
 romstage-y += mmap_boot.c
 romstage-y += tsc_freq.c
+romstage-y += pmutil.c
 
 smm-y += placeholders.c
+smm-y += pmutil.c
 
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi.c
 ramstage-y += cpu.c
@@ -42,6 +44,7 @@ ramstage-y += uart.c
 ramstage-y += northbridge.c
 ramstage-y += spi.c
 ramstage-y += tsc_freq.c
+ramstage-y += pmutil.c
 
 postcar-y += exit_car.S
 postcar-y += memmap.c