tools: termios_linux.h: Fix tcsendbreak() implementation

tools: termios_linux.h: Fix tcsendbreak() implementation

There are two Linux ioctls which implements tcsendbreak() functionality:
TCSBRK and TCSBRKP

TCSBRK with non-zero parameter implements tcdrain() and with zero parameter
implements tcsendbreak() for duration of 0.25s.

TCSBRKP with zero parameter is same as TCSBRK and with non-zero parameter
implements tcsendbreak() for duration in deciseconds specified by
parameter. TCSBRKP does not have to be provided by older toolchain
versions.

So tcsendbreak() has to either use TCSBRK with zero parameter or TCSBRKP
with any parameter.

Fix code to use TCSBRKP and fallback to TCSBRK with 0.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>