minor DaVinci clock cleanup

Minor cleanup to clock-related defines for DaVinci DM6446 boards:

 - CONFIG_SYS_CLK_FREQ is unused; remove it.

 - CONFIG_SYS_NS16550_CLK must be the same as CONFIG_SYS_HZ_CLOCK

On DM6446 both of those peripheral clocks actually come from the
same source, the primary oscillator.  Having them use the same
symbol avoids bugs in the clone'n'modify development cycle.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
diff --git a/include/configs/davinci_sffsdr.h b/include/configs/davinci_sffsdr.h
index 73a59db..c2ebd97 100644
--- a/include/configs/davinci_sffsdr.h
+++ b/include/configs/davinci_sffsdr.h
@@ -32,7 +32,6 @@
 				 * powering ON the DSP. */
 /* SoC Configuration */
 #define CONFIG_ARM926EJS			/* arm926ejs CPU core */
-#define CONFIG_SYS_CLK_FREQ	297000000	/* Arm Clock frequency */
 #define CONFIG_SYS_TIMERBASE		0x01c21400	/* use timer 0 */
 #define CONFIG_SYS_HZ_CLOCK		27000000	/* Timer Input clock freq */
 #define CONFIG_SYS_HZ			1000
@@ -56,7 +55,7 @@
 #define CONFIG_SYS_NS16550_SERIAL
 #define CONFIG_SYS_NS16550_REG_SIZE	-4	/* NS16550 register size, byteorder */
 #define CONFIG_SYS_NS16550_COM1	0x01c20000	/* Base address of UART0 */
-#define CONFIG_SYS_NS16550_CLK		27000000	/* Input clock to NS16550 */
+#define CONFIG_SYS_NS16550_CLK	CONFIG_SYS_HZ_CLOCK	/* Input clock to NS16550 */
 #define CONFIG_CONS_INDEX	1		/* use UART0 for console */
 #define CONFIG_BAUDRATE		115200		/* Default baud rate */
 #define CONFIG_SYS_BAUDRATE_TABLE	{ 9600, 19200, 38400, 57600, 115200 }