chromeos: vboot and chromeos dependency removal for sw write protect state

This removes the dependency on chromeos and vboot for the sw write protect state
function: vboot_get_sw_write_protect, renamed to get_sw_write_protect_state to
both reflect this change and become consistent with the definition of
get_write_protect_state that is already in use.

Change-Id: I47ce31530a03f6749e0f370e5d868466318b3bb6
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: http://review.coreboot.org/11496
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/vendorcode/google/chromeos/chromeos.h

@@ -68,8 +68,6 @@ static inline int vboot_get_handoff_info(void **addr, uint32_t *size)
 }
 #endif /* CONFIG_VBOOT_VERIFY_FIRMWARE */
 
-int vboot_get_sw_write_protect(void);
-
 #include "gnvs.h"
 struct device;