drm/bridge: anx7625: Fix edid_read break case in sp_tx_edid_read()

edid_read() was assumed to return 0 on success. After commit
7f16d0f3("drm/bridge: anx7625: Propagate errors from sp_tx_rst_aux()"),
the function will return > 0 for successful case, representing the i2c
read bytes. Otherwise -EIO on failure cases. Update the g_edid_break
break condition accordingly.

Fixes: 7f16d0f3

("drm/bridge: anx7625: Propagate errors from sp_tx_rst_aux()")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Xin Ji <xji@analogixsemi.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211118193002.407168-1-hsinyi@chromium.org