i2c: qup: fix the transfer length for BAM RX EOT FLUSH tags

In case of FLUSH operation, BAM copies INPUT EOT FLUSH (0x94)
instead of normal EOT (0x93) tag in input data stream when an
input EOT tag is received during flush operation. So only one tag
will be written instead of 2 separate tags.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>