fvp: Remove definition of BOARD_BOOTIMAGE_PARTITION_SIZE.

Now that https://r.android.com/1989408 and
https://r.android.com/1988815 allow avoiding specifying the size of
the boot partition by removing the definition of this variable, do so.

Change-Id: I83ec5179bf54cc99074fc6b508dfebfb8704530f
Bug: 142352330
1 file changed