rename i2c driver files using <type>-<driver name>

Follow the same order of <type>-<driver name>

Change-Id: Iac9f01f864c2ac76ee7aadf8cbdbb12835f39df4
Signed-off-by: Anas Nashif <anas.nashif@intel.com>

drivers/i2c/Makefile

@@ -1 +1 @@
-obj-$(CONFIG_I2C_DW) += dw_i2c.o
+obj-$(CONFIG_I2C_DW) += i2c-dw.o

drivers/i2c/i2c-dw.c

@@ -43,8 +43,8 @@
 #include <errno.h>
 #include <sys_io.h>
 
-#include "dw_i2c.h"
-#include "dw_i2c_registers.h"
+#include "i2c-dw.h"
+#include "i2c-registers.h"
 
 #ifndef CONFIG_I2C_DEBUG
 #define DBG(...) {;}