slippy/falco: Re-enable EC software sync

The EC was disabling flash commands and sysjump was not working
properly.  With those two fixed software sync works properly.

Google Chrome EC MKBP driver ready, id 'slippy_no_version'
Clearing the recovery request.
EC hash:7fea29992ef72e3e64d8ffe522aa1dfa68dcb44a2da96a4c19530ea1a0bd22c4
EC-RW hash address, size are 0xffa1cfe8, 32.
Hash = 727e79934d9394184da496cebc27f7275b9d2d91079bf125d8f977a1f8aa4cde
Expected hash:727e79934d9394184da496cebc27f7275b9d2d91079bf125d8f977a1f8aa4cde
EC-RW firmware address, size are 0xffad000c, 57180.
VbEcSoftwareSync() - expected len = 57180
Computed hash of expected image:727e79934d9394184da496cebc27f7275b9d2d91079bf125d8f977a1f8aa4cde
VbEcSoftwareSync() updating EC-RW...
VbEcSoftwareSync() jumping to EC-RW
VbEcSoftwareSync() in RW; done

Change-Id: I63ca00d6c94854f2b395eb736ce20792da5f8de2
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56821
Reviewed-on: http://review.coreboot.org/4208
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)

src/mainboard/google/falco/Kconfig

@@ -9,6 +9,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select INTEL_LYNXPOINT_LP
 	select BOARD_ROMSIZE_KB_8192
 	select EC_GOOGLE_CHROMEEC
+	select EC_SOFTWARE_SYNC
 	select HAVE_ACPI_TABLES
 	select HAVE_OPTION_TABLE
 	select HAVE_ACPI_RESUME

src/mainboard/google/slippy/Kconfig

@@ -9,6 +9,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select INTEL_LYNXPOINT_LP
 	select BOARD_ROMSIZE_KB_8192
 	select EC_GOOGLE_CHROMEEC
+	select EC_SOFTWARE_SYNC
 	select HAVE_ACPI_TABLES
 	select HAVE_OPTION_TABLE
 	select HAVE_ACPI_RESUME