cmake: Various refactorings and whitespace fixes

This commit applies various refactorings and whitespace fixes in
preparation for the patch that fixes #13001.

It includes changing indentation from tabs to spaces and splitting
tokens across more lines to increase readability and minimize patch
sizes.

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>

CMakeLists.txt

@@ -456,7 +456,9 @@ function(construct_add_custom_command_for_linker_pass linker_output_name output_
 
   set(${output_variable}
     OUTPUT ${linker_cmd_file_name}
-    DEPENDS ${LINKER_SCRIPT}
+    DEPENDS
+    ${LINKER_SCRIPT}
+    # NB: 'linker_script_dep' will use a keyword that ends 'DEPENDS'
     ${linker_script_dep}
     COMMAND ${CMAKE_C_COMPILER}
     -x assembler-with-cpp
@@ -746,7 +748,10 @@ if (CONFIG_CODE_DATA_RELOCATION)
   set(CODE_RELOCATION_DEP code_relocation_source_lib)
 endif() # CONFIG_CODE_DATA_RELOCATION
 
-construct_add_custom_command_for_linker_pass(linker custom_command)
+construct_add_custom_command_for_linker_pass(
+  linker
+  custom_command
+  )
 add_custom_command(
   ${custom_command}
 )
@@ -1147,7 +1152,10 @@ if(CONFIG_APP_SHARED_MEM AND CONFIG_USERSPACE)
 endif()
 
 if(CONFIG_USERSPACE AND CONFIG_ARM)
-  construct_add_custom_command_for_linker_pass(linker_priv_stacks custom_command)
+  construct_add_custom_command_for_linker_pass(
+    linker_priv_stacks
+    custom_command
+    )
   add_custom_command(
     ${custom_command}
     )
@@ -1188,7 +1196,10 @@ if(GKOF OR GKSF)
   # The second linker pass uses the same source linker script of the
   # first pass (LINKER_SCRIPT), but this time with a different output
   # file and preprocessed with the define LINKER_PASS2.
-  construct_add_custom_command_for_linker_pass(linker_pass_final custom_command)
+  construct_add_custom_command_for_linker_pass(
+    linker_pass_final
+    custom_command
+    )
   add_custom_command(
     ${custom_command}
     )