tpm: don't use unneeded double brackets

clang is tempted to inteprete such a condition as a assignment
as well. Since it isn't don't use double brackets.

cc: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

drivers/tpm/tpm.c

@@ -411,7 +411,7 @@ static ssize_t tpm_transmit(const unsigned char *buf, size_t bufsiz)
 			goto out_recv;
 		}
 
-		if ((status == chip->vendor.req_canceled)) {
+		if (status == chip->vendor.req_canceled) {
 			error("Operation Canceled\n");
 			rc = -ECANCELED;
 			goto out;