drm/atomic-helper: Bump vblank timeout to 100 ms

mainline inclusion
from mainline-v5.3-rc1
commit b3198c38
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MBKM?from=project-issue
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b3198c38f02d54a5e964258a2180d502abe6eaf0



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The 50 ms default timeout waiting for vblanks is too small
for the first vblank from the ST-Ericsson MCDE display
controller over DSI. Presumably this is because the DSI
display is command-mode only and the state machine will
take some time setting up its state for the first display
update, and we hit a timeout. 100 ms makes it pass without
problems.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190430093746.26485-1-linus.walleij@linaro.org


Signed-off-by: zhanghua <zhanghua_yewu@cmss.chinamobile.com>