fvp: Move TSP from Secure DRAM to Secure SRAM

fvp: Move TSP from Secure DRAM to Secure SRAM

The TSP used to execute from secure DRAM on the FVPs because there was
not enough space in Trusted SRAM to fit it in. Thanks to recent RAM
usage enhancements being implemented, we have made enough savings for
the TSP to execute in SRAM.

However, there is no contiguous free chunk of SRAM big enough to hold
the TSP. Therefore, the different bootloader images need to be moved
around to reduce memory fragmentation. This patch keeps the overall
memory layout (i.e. keeping BL1 R/W at the bottom, BL2 at the top and
BL3-1 in between) but moves the base addresses of all the bootloader
images in such a way that:
 - memory fragmentation is reduced enough to fit BL3-2 in;
 - new base addresses are suitable for release builds as well as debug
   ones;
 - each image has a few extra kilobytes for future growth.
   BL3-1 and BL3-2 are the images which received the biggest slice
   of the cake since they will most probably grow the most.

A few useful numbers for reference (valid at the time of this patch):
        |-----------------------|-------------------------------
        |  image size (debug)   |  extra space for the future
--------|-----------------------|-------------------------------
BL1 R/W |         20 KB         |            4 KB
BL2     |         44 KB         |            4 KB
BL3-1   |        108 KB         |           12 KB
BL3-2   |         56 KB         |            8 KB
--------|-----------------------|-------------------------------
Total   |        228 KB         |           28 KB       = 256 KB
--------|-----------------------|-------------------------------

Although on FVPs the TSP now executes from Trusted SRAM by default,
this patch keeps the option to execute it from Trusted DRAM. This is
controlled by the build configuration 'TSP_RAM_LOCATION'.

Fixes ARM-Software/tf-issues#81

Change-Id: Ifb9ef2befa9a2d5ac0813f7f79834df7af992b94