linux-user/sh4/termbits: Silence warning about TIOCSER_TEMT double definition

linux-user/sh4/termbits: Silence warning about TIOCSER_TEMT double definition

Seen while compiling on Alpine:

 In file included from ../linux-user/strace.c:17:
 In file included from ../linux-user/qemu.h:11:
 In file included from ../linux-user/syscall_defs.h:1247:
 ../linux-user/sh4/termbits.h:276:10: warning: 'TIOCSER_TEMT' macro redefined
  [-Wmacro-redefined]
 # define TIOCSER_TEMT    0x01   /* Transmitter physically empty */
          ^
 /usr/include/sys/ioctl.h:50:9: note: previous definition is here
 #define TIOCSER_TEMT 1
         ^
 1 warning generated.

Add the TARGET_ prefix here, too, like we do it on the other architectures.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Message-Id: <20220330134302.979686-1-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>