tools/power/acpi: Serialize Makefile

Before this patch you get tools/power/acpi/Makefile.rules
included in parallel trying to copy KERNEL_INCLUDE multiple
times:

make -j20 acpi
DESCEND power/acpi
DESCEND tools/acpidbg
DESCEND tools/acpidump
DESCEND tools/ec
MKDIR include
MKDIR include
MKDIR include
CP include
CP include
cp: cannot create directory '/home/abuild/rpmbuild/BUILD/linux-5.7.7+git20200917.10b82d517648/tools/power/acpi/include/acpi': File exists
make[2]: *** [../../Makefile.rules:20: /home/abuild/rpmbuild/BUILD/linux-5.7.7+git20200917.10b82d517648/tools/power/acpi/include] Error 1
make[1]: *** [Makefile:16: acpidbg] Error 2
make[1]: *** Waiting for unfinished jobs....

with this patch each subdirectory will be processed serialized:

DESCEND power/acpi
DESCEND tools/acpidbg
MKDIR include
CP include
CC tools/acpidbg/acpidbg.o
LD acpidbg
STRIP acpidbg
DESCEND tools/acpidump
CC tools/acpidump/apdump.o
...
LD acpidump
STRIP acpidump
DESCEND tools/ec
CC tools/ec/ec_access.o
LD ec
STRIP ec

Signed-off-by: Thomas Renninger <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

tools/power/acpi/Makefile

···
 
 include ../../scripts/Makefile.include
 
+.NOTPARALLEL:
+
 all: acpidbg acpidump ec
 clean: acpidbg_clean acpidump_clean ec_clean
 install: acpidbg_install acpidump_install ec_install