riscv: andes_plic: Fix riscv_get_ipi() mask

Current logic in riscv_get_ipi() for Andes PLICSW does not look
correct. The mask to test IPI pending bits for a hart should be
left shifted by (8 * gd->arch.boot_hart), just the same as what
is done in riscv_send_ipi().

Fixes: 8b3e97ba ("riscv: add functions for reading the IPI status")
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Tested-by: Rick Chen <rick@andestech.com>
40 jobs for master in 65 minutes and 43 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Testsuites
passed #280074
Build envtools

00:00:13

passed #280073
Build tools-only

00:00:28

passed #280072
Check for configs without MAINTAINERS entry

00:00:11

passed #280068
cppcheck

00:00:53

passed #280069
grep TODO/FIXME/HACK

00:00:27

passed #280070
htmldocs

00:00:52

passed #280075
Run binman, buildman, dtoc, Kconfig and patman testsuites

00:01:07

passed #280076
Run tests for Nokia RX-51 (aka N900)

00:03:19

passed #280071
sloccount

00:00:55

 
  Test.Py
passed #280081
evb-ast2500 test.py

00:00:39

passed #280083
integratorcp_cm926ejs test.py

00:00:58

passed #280085
qemu_arm64 test.py

00:01:20

passed #280084
qemu_arm test.py

00:01:40

passed #280089
qemu_malta64el test.py

00:00:37

passed #280088
qemu_malta64 test.py

00:01:00

passed #280087
qemu_maltael test.py

00:01:00

passed #280086
qemu_malta test.py

00:01:00

passed #280090
qemu-ppce500 test.py

00:01:02

passed #280093
qemu-riscv32_spl test.py

00:01:08

passed #280091
qemu-riscv32 test.py

00:00:58

passed #280094
qemu-riscv64_spl test.py

00:00:47

passed #280092
qemu-riscv64 test.py

00:01:23

passed #280096
qemu-x86_64 test.py

00:01:43

passed #280095
qemu-x86 test.py

00:01:36

passed #280097
r2dplus_i82557c test.py

00:00:37

passed #280098
r2dplus_pcnet test.py

00:00:38

passed #280099
r2dplus_rtl8139 test.py

00:00:42

passed #280100
r2dplus_tulip test.py

00:01:00

passed #280082
sandbox_flattree test.py

00:00:56

passed #280080
sandbox_noinst_test.py

00:01:17

passed #280079
sandbox_spl test.py

00:01:18

passed #280077
sandbox test.py

00:03:45

passed #280078
sandbox with clang test.py

00:03:27

passed #280102
xilinx_versal_virt test.py

00:00:40

passed #280101
xilinx_zynq_virt test.py

00:01:09

passed #280103
xtfpga test.py

00:00:58

 
  World Build
passed #280104
build all 32bit ARM platforms

00:48:35

passed #280105
build all 64bit ARM platforms

00:17:44

passed #280107
build all other platforms

00:05:22

passed #280106
build all PowerPC platforms

00:05:50