linux-user: add rt_tgsigqueueinfo() strace

This commit improves strace support for syscall rt_tgsigqueueinfo().

Prior to this commit, typical strace output used to look like this:
7775 rt_tgsigqueueinfo(7775,7775,50,1996483164,0,0) = 0

After this commit, it looks like this:
7775 rt_tgsigqueueinfo(7775,7775,50,0x76ffea5c) = 0

Signed-off-by: Miloš Stojanović <Milos.Stojanovic@rt-rk.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>