treewide: remove meaningless assignments in Makefiles

treewide: remove meaningless assignments in Makefiles

In Makefiles, $(error ), $(warning ), and $(info ) expand to the empty
string, as explained in the GNU Make manual [1]:
 "The result of the expansion of this function is the empty string."

Therefore, they are no-op except for logging purposes.

$(shell ...) expands to the output of the command. It expands to the
empty string when the command does not print anything to stdout.
Hence, $(shell mkdir ...) is no-op except for creating the directory.

Remove meaningless assignments.

[1]: https://www.gnu.org/software/make/manual/make.html#Make-Control-Functions

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Arnaldo Carvalho de Melo <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]