hwrng: optee - remove redundant initialization to variable rng_size

Variable rng_size is being initialized with a value that is never read,
the variable is being re-assigned later on. The initialization is
redundant and can be removed.

Cleans up cppcheck warning:
Variable 'rng_size' is assigned a value that is never used.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/optee-rng.c

@@ -115,7 +115,7 @@ static size_t get_optee_rng_data(struct optee_rng_private *pvt_data,
 static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 {
 	struct optee_rng_private *pvt_data = to_optee_rng_private(rng);
-	size_t read = 0, rng_size = 0;
+	size_t read = 0, rng_size;
 	int timeout = 1;
 	u8 *data = buf;