The patch changes the layout of BL images in memory to enable
more efficient use of available space. Previously BL31 was loaded
with the expectation that BL2 memory would be reclaimed by BL32
loaded in SRAM. But with increasing memory requirements in the
firmware, we can no longer fit BL32 in SRAM anymore which means the
BL2 memory is not reclaimed by any runtime image. Positioning BL2
below BL1-RW and above BL31 means that the BL31 NOBITS can be
overlaid on BL2 and BL1-RW.

This patch also propogates the same memory layout to BL32 for AArch32
mode. The reset addresses for the following configurations are also
changed :
   * When RESET_TO_SP_MIN=1 for BL32 in AArch32 mode
   * When BL2_AT_EL3=1 for BL2

The restriction on BL31 to be only in DRAM when SPM is enabled
is now removed with this change. The update to the firmware design
guide for the BL memory layout is done in the following patch.

Change-Id: Icca438e257abe3e4f5a8215f945b9c3f9fbf29c9
Signed-off-by: Soby Mathew <soby.mathew@arm.com>