hw/char/exynos4210_uart: Drop unused local variable frame_size

The frame_size local variable in exynos4210_uart_update_parameters()
is calculated but never used (and has been this way since the
device was introduced in commit e5a4914e). The qemu_chr_fe_ioctl()
doesn't need this information (if it really wanted it it could
calculate it from the parity/data_bits/stop_bits), so just drop
the variable entirely.

Fixes: https://bugs.launchpad.net/bugs/1655702



Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1484589515-26353-1-git-send-email-peter.maydell@linaro.org