comgt: Use TCGETS and TCSETS ioctls for struct termios

When passing struct termios to ioctl TCGETS and TCSETS should be
used instead of TCGETA and TCSETA, which are meant for the older
struct termio. Should fix https://dev.openwrt.org/ticket/19012



Signed-off-by: Matti Laakso <malaakso@elisanet.fi>

SVN-Revision: 44506