exynos5250: add missing address-of operator in UART driver

This adds a missing address-of operator. This was a subtle bug that
didn't seem to cause problems at first since the serial console
appeared to work. However it caused an imprecise external abort which
became apparent later on when aborts were unmasked in the kernel via
the CPSR_A bit.

(credit goes to Gabe Black for finding this)
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Change-Id: I80a33b147d92d559fa8fefbe7d5642235deb9aea
Reviewed-on: http://review.coreboot.org/3038
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/cpu/samsung/exynos5250/uart.c

@@ -185,7 +185,7 @@ static void exynos5_uart_tx_byte(unsigned char data)
 	struct s5p_uart *uart = (struct s5p_uart *)base_port;
 
 	/* wait for room in the tx FIFO */
-	while ((readl(uart->ufstat) & TX_FIFO_FULL_MASK)) {
+	while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) {
 		if (exynos5_uart_err_check(1))
 			return;
 	}