sofia3gr: ion: fix this issue, the reason is ion_import_dma_buf may be invoked concur...

sofia3gr: ion: fix this issue, the reason is ion_import_dma_buf may be invoked concurrently.

<4>[ 3123.242655] WARNING: CPU: 2 PID: 2648 at drivers/staging/android/ion/ion.c:512 ion_handle_add+0xb4/0xc0()
<7>[ 3123.252189] ion_handle_add: buffer already found.
<7>[ 3123.256694] Modules linked in: iwlmvm iwlwifi mac80211 cfg80211 compat
<7>[ 3123.263195] CPU: 2 PID: 2648 Comm: TimedEventQueue Tainted: G        W    3.14.0 #7
<7>[ 3123.270868]  00000000 00000000 9a3efd2c 80faf273 9a3efd6c 9a3efd5c 80935dc9 811d7fd3
<7>[ 3123.278405]  9a3efd88 00000a58 812208a0 00000200 80e128d4 80e128d4 8d4ae00c a8cd8600
<7>[ 3123.286065]  a8cd8094 9a3efd74 80935e0e 00000009 9a3efd6c 811d7fd3 9a3efd88 9a3efd9c
<7>[ 3123.293867] Call Trace:
<7>[ 3123.296159]  [<80faf273>] dump_stack+0x48/0x69
<7>[ 3123.300537]  [<80935dc9>] warn_slowpath_common+0x79/0x90
<7>[ 3123.305913]  [<80e128d4>] ? ion_handle_add+0xb4/0xc0
<7>[ 3123.310694]  [<80e128d4>] ? ion_handle_add+0xb4/0xc0
<7>[ 3123.315703]  [<80935e0e>] warn_slowpath_fmt+0x2e/0x30
<7>[ 3123.320586]  [<80e128d4>] ion_handle_add+0xb4/0xc0
<7>[ 3123.325450]  [<80e144cc>] ion_import_dma_buf+0x8c/0x110
<7>[ 3123.330490]  [<80c517c4>] reg_init+0x364/0x7d0
<7>[ 3123.334975]  [<80993363>] ? futex_wait+0x123/0x210
<7>[ 3123.339607]  [<80992e0e>] ? get_futex_key+0x16e/0x1e0
<7>[ 3123.344692]  [<8099308f>] ? futex_wake+0x5f/0x120
<7>[ 3123.349245]  [<80c51e19>] vpu_service_ioctl+0x1e9/0x500
<7>[ 3123.354508]  [<80994aec>] ? do_futex+0xec/0x8e0
<7>[ 3123.358885]  [<80971080>] ? prepare_to_wait_event+0xc0/0xc0
<7>[ 3123.364503]  [<80c51c30>] ? reg_init+0x7d0/0x7d0
<7>[ 3123.368955]  [<80a22562>] do_vfs_ioctl+0x2d2/0x4c0
<7>[ 3123.373816]  [<80b198ad>] ? inode_has_perm.isra.41+0x2d/0x40
<7>[ 3123.379278]  [<80b199cf>] ? file_has_perm+0x7f/0x90
<7>[ 3123.384217]  [<80b1a5f7>] ? selinux_file_ioctl+0x47/0xf0
<7>[ 3123.389351]  [<80a227a8>] SyS_ioctl+0x58/0x80
<7>[ 3123.393754]  [<80fb45e8>] syscall_call+0x7/0x7
<7>[ 3123.398043]  [<80fb0000>] ? mmc_do_calc_max_discard+0xab/0xe4
<4>[ 3123.404220] ---[ end trace bd195cf65df321ce ]---

Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
Signed-off-by: CMY <cmy@rock-chips.com>