Fix invert for pocketbooks by disabling hardware invert (#8803)

With the inkview library inverting the screen seems possible but needs some 
discussion with the developers of Pocketbook. For now disable HWInvert so 
this feature is not broken while we figure out how to change the invert with inkview.

base

@@ -1 +1 @@
-Subproject commit 64bdeda85efe127357c9b969a8cc72b46521ad87
+Subproject commit 91c1285b7e51b4da6c202d367b8af9a37a7a0a93

frontend/device/pocketbook/device.lua

@@ -42,7 +42,10 @@ local PocketBook = Generic:new{
     -- NOTE: Apparently, HW inversion is a pipedream on PB (#6669), ... well, on sunxi chipsets anyway.
     -- For which we now probe in fbinfoOverride() and tweak the flag to "no".
     -- NTX chipsets *should* work (PB631), but in case it doesn't on your device, set this to "no" in here.
-    canHWInvert = yes,
+    --
+    -- The above comment applied to rendering without inkview. With the inkview library HW inverting the
+    -- screen is not possible. For now disable HWInvert for all devices.
+    canHWInvert = no,
 
     -- If we can access the necessary devices, input events can be handled directly.
     -- This improves latency (~40ms), as well as power usage - we can spend more time asleep,