usb: mtu3: flush cache for the first GPD when allocate GPD ring

When allocate the GPD ring, and tell its address to the controller, then
the driver starts or resumes the QMU, the controller will try to access
the first GPD, so need flush the first one to avoid wrong GPD status.

Reported-by: Xin Lin <Xin.Lin@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
43 jobs for master in 36 minutes and 41 seconds (queued for 4 seconds)
Status Name Job ID Coverage
  Testsuites
passed Build envtools #346021

00:00:13

passed Build tools-only #346020

00:00:11

passed Check for configs without MAINTAINERS entry #346019

00:00:08

passed cppcheck #346015

00:01:30

passed grep TODO/FIXME/HACK #346016

00:00:14

passed htmldocs #346017

00:00:49

passed Run binman, buildman, dtoc, Kconfig and patman testsuites #346022

00:00:48

passed Run tests for Nokia RX-51 (aka N900) #346023

00:03:27

passed sloccount #346018

00:00:22

 
  Test.Py
passed evb-ast2500 test.py #346028

00:00:31

passed integratorcp_cm926ejs test.py #346031

00:00:30

passed qemu_arm64 test.py #346033

00:01:11

passed qemu_arm test.py #346032

00:01:10

passed qemu_malta64el test.py #346037

00:00:50

passed qemu_malta64 test.py #346036

00:00:31

passed qemu_maltael test.py #346035

00:00:54

passed qemu_malta test.py #346034

00:00:32

passed qemu-ppce500 test.py #346038

00:00:31

passed qemu-riscv32_spl test.py #346041

00:00:59

passed qemu-riscv32 test.py #346039

00:01:21

passed qemu-riscv64_spl test.py #346042

00:01:11

passed qemu-riscv64 test.py #346040

00:00:53

passed qemu-x86_64 test.py #346044

00:01:31

passed qemu-x86 test.py #346043

00:01:06

passed r2dplus_i82557c test.py #346045

00:00:31

passed r2dplus_pcnet test.py #346046

00:01:00

passed r2dplus_rtl8139 test.py #346047

00:00:31

passed r2dplus_tulip test.py #346048

00:00:49

passed sandbox_flattree test.py #346029

00:00:51

passed sandbox_noinst_test.py #346027

00:00:48

passed sandbox_spl test.py #346026

00:00:49

passed sandbox test.py #346024

00:06:38

passed sandbox with clang test.py #346025

00:07:38

passed sifive_unleashed_sdcard test.py #346049

00:01:18

passed sifive_unleashed_spi-nor test.py #346050

00:00:40

passed vexpress_ca9x4 test.py #346030

00:00:37

passed xilinx_versal_virt test.py #346052

00:00:32

passed xilinx_zynq_virt test.py #346051

00:00:54

passed xtfpga test.py #346053

00:00:30

 
  World Build
passed build all 32bit ARM platforms #346054

00:12:59

passed build all 64bit ARM platforms #346055

00:16:36

passed build all other platforms #346057

00:10:31

passed build all PowerPC platforms #346056

00:08:30