In commit a8d25326 we cleaned up usage of the qemu-common.h header
so that it was always included from .c files and never from other .h files.
We missed adding it to net/tap-solaris.c (which previously was pulling it
in via tap-int.h), which broke building on Solaris hosts.

Fixes: a8d25326
Reported-by: Michele Denber <denber@mindspring.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Michele Denber <denber@mindspring.com>
Message-Id: <20200704092317.12943-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>