MX5: added CONFIG_PMIC_FSL_MC13892 to mx53evk

Recent patches adding FSL_PMIC_I2C_LENGTH require
that the PMIC model is defined.

Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Jason Liu <jason.hui@linaro.org>

include/configs/mx53evk.h

@@ -59,6 +59,7 @@
 #define CONFIG_PMIC_I2C
 #define CONFIG_PMIC_FSL
 #define CONFIG_SYS_FSL_PMIC_I2C_ADDR    8
+#define CONFIG_PMIC_FSL_MC13892
 #define CONFIG_RTC_MC13XXX
 
 /* MMC Configs */