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/include/bootmode.h

@@ -23,6 +23,7 @@
 /* functions implemented per mainboard: */
 void init_bootmode_straps(void);
 int get_write_protect_state(void);
+int get_sw_write_protect_state(void);
 int get_developer_mode_switch(void);
 int get_recovery_mode_switch(void);
 int clear_recovery_mode_switch(void);