linux-user: add tkill(), tgkill() and rt_sigqueueinfo() strace

linux-user: add tkill(), tgkill() and rt_sigqueueinfo() strace

Improve strace support for syscall tkill(), tgkill() and rt_sigqueueinfo()
by implementing print functions that match arguments types of the system
calls and add them to the corresponding starce.list entry.

tkill:
Prior to this commit, typical strace output used to look like this:
4886 tkill(4886,50,0,4832615904,0,-9151031864016699136) = 0
After this commit, it looks like this:
4886 tkill(4886,50) = 0

tgkill:
Prior to this commit, typical strace output used to look like this:
4890 tgkill(4890,4890,50,8,4832630528,4832615904) = 0
After this commit, it looks like this:
4890 tgkill(4890,4890,50) = 0

rt_sigqueueinfo:
Prior to this commit, typical strace output used to look like this:
8307 rt_sigqueueinfo(8307,50,1996483164,0,0,50) = 0
After this commit, it looks like this:
8307 rt_sigqueueinfo(8307,50,0x00000040007ff6b0) = 0

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