linux-user: fix inconsistent spaces in print_siginfo() output

This patch improves the consistentcy of the output from print_siginfo()
by removing spaces around the equal sign of si_pid, si_uid, si_timer1,
si_timer2, si_band, si_fd, si_addr, si_status and si_sigval. This way
they match si_signo and ci_code. Host strace was used as a reference
for this chage.

Prior to this commit, typical strace output used to look like this:

Signed-off-by: Riku Voipio <riku.voipio@linaro.org>