readonly: fix condition showing readonly checkbox

Non dynamic partition devices need this if accidentally
turned off.

Change-Id: I0a212a8fc6446dfa6d82cf1103f4e4e80e680f89
diff --git a/gui/theme/common/portrait.xml b/gui/theme/common/portrait.xml
index b1cca6f..0fed73d 100755
--- a/gui/theme/common/portrait.xml
+++ b/gui/theme/common/portrait.xml
@@ -2738,7 +2738,7 @@
 
 			<button style="checkbox">
 				<conditions>
-					<condition var1="tw_mount_system_ro" op="!=" var2="0"/>
+					<condition var1="tw_mount_system_ro" op="=" var2="0"/>
 					<condition var1="tw_is_super" op="=" var2="0"/>
 				</conditions>
 				<placement x="%indent%" y="%row15a_y%" textplacement="6"/>