drm: qxl: remove pr_info message, stops log spamming

drm: qxl: remove pr_info message, stops log spamming

Simply mmap'ing /dev/dri/card0 repeatedly will spam the kernel
log with qxl_mmap information messages. The following example code
illustrates this:

int main(void)
{
	int fd = open("/dev/dri/card0", O_RDONLY);
	if (fd == -1)
		err(1, "open failed");

	for (;;) {
		void *m = mmap(NULL, 4096, PROT_READ,
			MAP_SHARED, fd, 0);
		if (m != MAP_FAILED)
			munmap(m, 4096);
	}
}

Stop the spamming by removing the pr_info message. Since the mmap'ing
returns -EINVAL there is no need for the pr_info message.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170912173422.14062-1-colin.king@canonical.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>