[build] Remove kindle5 target (#3902)

Makefile

@@ -364,8 +364,6 @@ ifeq ($(TARGET), kindle)
 	make kindleupdate
 else ifeq ($(TARGET), kindle-legacy)
 	make kindleupdate
-else ifeq ($(TARGET), kindle5)
-	make kindleupdate
 else ifeq ($(TARGET), kindlepw2)
 	make kindleupdate
 else ifeq ($(TARGET), kobo)

kodev

@@ -109,10 +109,9 @@ function kodev-fetch-thirdparty() {
 }
 
 SUPPORTED_TARGETS="
-    kindle          For kindle with touch support
-    kindle5         For kindle models >= kindle4 < paper white 2
-    kindlepw2       For kindle models >= paper white 2
-    kindle-legacy   For kindle2/3/DXG
+    kindle          Compatible with all Kindle models >= Kindle4
+    kindlepw2       With compiler optimizations for Kindle models >= Paperwhite 2
+    kindle-legacy   Needed only for Kindle2/3/DXG
     kobo
     android
     pocketbook
@@ -169,10 +168,6 @@ ${SUPPORTED_TARGETS}"
             make TARGET=kindle
             assert_ret_zero $?
             ;;
-        kindle5)
-            make TARGET=kindle5
-            assert_ret_zero $?
-            ;;
         kindlepw2)
             make TARGET=kindlepw2
             assert_ret_zero $?
@@ -251,9 +246,6 @@ ${SUPPORTED_TARGETS}"
         kindle)
             make TARGET=kindle clean
             ;;
-        kindle5)
-            make TARGET=kindle5 clean
-            ;;
         kindlepw2)
             make TARGET=kindlepw2 clean
             ;;
@@ -348,10 +340,6 @@ ${SUPPORTED_RELEASE_TARGETS}"
             kodev-build kindle
             make TARGET=kindle update
             ;;
-        kindle5)
-            kodev-build kindle5
-            make TARGET=kindle5 update
-            ;;
         kindlepw2)
             kodev-build kindlepw2
             make TARGET=kindlepw2 update