cmake: delete obsolete deprecation checks

FLASH_SCRIPT and DEBUG_SCRIPT are way gone; no need to check for them
anymore.

Signed-off-by: Marti Bolivar <marti.bolivar@nordicsemi.no>

cmake/extensions.cmake

@@ -1273,9 +1273,9 @@ macro(assert test comment)
 endmacro()
 
 # Usage:
-#   assert_not(FLASH_SCRIPT "FLASH_SCRIPT has been removed; use BOARD_FLASH_RUNNER")
+#   assert_not(OBSOLETE_VAR "OBSOLETE_VAR has been removed; use NEW_VAR instead")
 #
-# will cause a FATAL_ERROR and print an errorm essage if the first
+# will cause a FATAL_ERROR and print an error message if the first
 # espression is true
 macro(assert_not test comment)
   if(${test})

cmake/flash/CMakeLists.txt

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-assert_not(FLASH_SCRIPT "FLASH_SCRIPT has been removed; use BOARD_FLASH_RUNNER")
-assert_not(DEBUG_SCRIPT "DEBUG_SCRIPT has been removed; use BOARD_DEBUG_RUNNER")
-
 get_property(RUNNERS GLOBAL PROPERTY ZEPHYR_RUNNERS)
 
 # Enable verbose output, if requested.