i2c: designware: Add comment to custom register value constants

DW_IC_COMP_VERSION register contains the ASCII representation of the
Synopsys component version. Here 0x3131312A == "111*" means version
1.11* required for DW_IC_SDA_HOLD register availability where '*' means
any letter starting from 'a'.

DW_IC_COMP_TYPE is constant and is derived from two ASCII letters "DW"
followed by a 16-bit unsigned number.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-designware-core.h

@@ -79,9 +79,9 @@
 #define DW_IC_CLR_RESTART_DET			0xa8
 #define DW_IC_COMP_PARAM_1			0xf4
 #define DW_IC_COMP_VERSION			0xf8
-#define DW_IC_SDA_HOLD_MIN_VERS			0x3131312A
+#define DW_IC_SDA_HOLD_MIN_VERS			0x3131312A /* "111*" == v1.11* */
 #define DW_IC_COMP_TYPE				0xfc
-#define DW_IC_COMP_TYPE_VALUE			0x44570140
+#define DW_IC_COMP_TYPE_VALUE			0x44570140 /* "DW" + 0x0140 */
 
 #define DW_IC_INTR_RX_UNDER			BIT(0)
 #define DW_IC_INTR_RX_OVER			BIT(1)