cm: build: kernel: Remove obsolete checks

 * BOARD_USES_UBOOT is unused.
 * Same goes for BOARD_USES_UNCOMPRESSED_BOOT. Furthermore,
   it is superseded by TARGET_USES_UNCOMPRESSED_KERNEL.

Change-Id: I9f0e2848fcd0cd212bccacf14df55ad03f821051
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 2e81f1b..8c45756 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -140,16 +140,6 @@
     KERNEL_ADDITIONAL_CONFIG_SRC := /dev/null
 endif
 
-## Do be discontinued in a future version. Notify builder about target
-## kernel format requirement
-ifeq ($(BOARD_KERNEL_IMAGE_NAME),)
-ifeq ($(BOARD_USES_UBOOT),true)
-        $(error "Please set BOARD_KERNEL_IMAGE_NAME to uImage")
-else ifeq ($(BOARD_USES_UNCOMPRESSED_BOOT),true)
-        $(error "Please set BOARD_KERNEL_IMAGE_NAME to Image")
-endif
-endif
-
 ifeq "$(wildcard $(KERNEL_SRC) )" ""
     ifneq ($(TARGET_PREBUILT_KERNEL),)
         HAS_PREBUILT_KERNEL := true