tools: buildman: Change default output directory to /tmp/buildman

When '-o' is not given to buildman, it defaults to use '../' as
the output directory, which is not a good practice as we don't
know whether we have the permission to do so.

Let's use /tmp/buildman as the default output directoy.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
31 jobs for u-boot-azure in 133 minutes and 4 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Testsuites
passed #24935
all
Build envtools

00:00:25

passed #24934
all
Build tools-only

00:00:26

passed #24933
all
Check for configs without MAINTAINERS entry

00:00:23

passed #24930
all
cppcheck

00:07:17

passed #24931
all
grep TODO/FIXME/HACK

00:01:17

passed #24936
all
Run binman, buildman, dtoc and patman testsuites

00:01:01

passed #24932
all
sloccount

00:00:46

 
  Test.Py
passed #24939
all
evb-ast2500 test.py

00:00:51

passed #24943
all
integratorcp_cm926ejs test.py

00:00:45

passed #24945
all
qemu_arm64 test.py

00:01:15

passed #24944
all
qemu_arm test.py

00:01:15

passed #24949
all
qemu_mips64el test.py

00:00:45

passed #24948
all
qemu_mips64 test.py

00:00:45

passed #24947
all
qemu_mipsel test.py

00:00:45

passed #24946
all
qemu_mips test.py

00:00:46

passed #24950
all
qemu-ppce500 test.py

00:00:44

passed #24951
all
qemu-riscv64 test.py

00:01:05

passed #24953
all
qemu-x86_64 test.py

00:01:21

passed #24952
all
qemu-x86 test.py

00:01:25

passed #24940
all
sandbox_flattree test.py

00:01:04

passed #24938
all
sandbox_spl test.py

00:00:58

passed #24937
all
sandbox test.py

00:01:50

passed #24941
all
vexpress_ca15_tc2 test.py

00:00:56

passed #24942
all
vexpress_ca9x4 test.py

00:00:47

passed #24955
all
xilinx_versal_virt test.py

00:00:47

passed #24956
all
xtfpga test.py

00:00:45

passed #24954
all
zynq_zc702 test.py

00:00:50

 
  World Build
passed #24957
all
build all 32bit ARM platforms

00:51:09

passed #24958
all
build all 64bit ARM platforms

00:18:30

passed #24960
all
build all other platforms

00:11:11

passed #24959
all
build all PowerPC platforms

00:20:46