berlna: unset BOARD_USERDATAIMAGE_PARTITION_SIZE

This not only saves a lot of build time when building with
TARGET_USERIMAGES_SPARSE_EXT_DISABLED and/or
TARGET_USERIMAGES_SPARSE_F2FS_DISABLED which is required
on A14, but also removes the need for the build system to
temporarily create a 40+GB userdata image.
Which means that less free space is required to start the
build.

Change-Id: Ibf48e7cdf566a4653e85352a79170b354d917234

BoardConfig.mk

@@ -29,7 +29,6 @@ TARGET_MODULE_ALIASES += \
     wlan.ko:qca_cld3_qca6750.ko
 
 # Partitions
-BOARD_USERDATAIMAGE_PARTITION_SIZE := 237371371520
 BOARD_MOT_DP_GROUP_SIZE := 7916748800
 BOARD_SUPER_PARTITION_SIZE := 15854469120