Introduce FLASHPROG_FLAG_NON_VOLATILE_WRSR

Add a new flag to our flash context that tells us if we should use
volatile or non-volatile status-register writes by default. Use it
in the write-protection API. The logic to disable block protection
automatically stays as is for now, until we have established tools
to manually control the protection.

Change-Id: Ie9a41b6404991075e2bf76bcffbd4e9887c62c79
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/193
diff --git a/include/libflashprog.h b/include/libflashprog.h
index 40050e3..a2ea63c 100644
--- a/include/libflashprog.h
+++ b/include/libflashprog.h
@@ -65,6 +65,7 @@
 	FLASHPROG_FLAG_FORCE_BOARDMISMATCH,
 	FLASHPROG_FLAG_VERIFY_AFTER_WRITE,
 	FLASHPROG_FLAG_VERIFY_WHOLE_CHIP,
+	FLASHPROG_FLAG_NON_VOLATILE_WRSR,
 };
 void flashprog_flag_set(struct flashprog_flashctx *, enum flashprog_flag, bool value);
 bool flashprog_flag_get(const struct flashprog_flashctx *, enum flashprog_flag);