siemens: eeprom: simplify setup & read

Since we have boards using the driver model or not for i2c, use abstraction
function to probe the i2c, check the EEPROM and read from EEPROM.

Signed-off-by: Enrico Leto <enrico.leto@siemens.com>
diff --git a/board/siemens/common/eeprom.h b/board/siemens/common/eeprom.h
index a21d427..a5ef5ab 100644
--- a/board/siemens/common/eeprom.h
+++ b/board/siemens/common/eeprom.h
@@ -18,4 +18,7 @@
 #define SIEMENS_EE_ADDR_CHIP		0x120
 #define SIEMENS_EE_ADDR_FACTORYSET	0x400
 
+int siemens_ee_setup(void);
+int siemens_ee_read_data(uint address, uchar *buffer, int len);
+
 #endif /* _COMMON_EEPROM_H_ */