TI: Rework SRAM definitions and maximums

TI: Rework SRAM definitions and maximums

On all TI platforms the ROM defines a "downloaded image" area at or near
the start of SRAM which is followed by a reserved area.  As it is at
best bad form and at worst possibly harmful in corner cases to write in
this reserved area, we stop doing that by adding in the define
NON_SECURE_SRAM_IMG_END to say where the end of the downloaded image
area is and make SRAM_SCRATCH_SPACE_ADDR be one kilobyte before this.
At current we define the end of scratch space at 0x228 bytes past the
start of scratch space this this gives us a lot of room to grow.  As
these scratch uses are non-optional today, all targets are modified to
respect this boundary.

Tested on OMAP4 Pandaboard, OMAP3 Beagle xM

Cc: Albert Aribaud <[email protected]>
Cc: Nagendra T S <[email protected]>
Cc: Vaibhav Hiremath <[email protected]>
Cc: Lokesh Vutla <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Igor Grinberg <[email protected]>
Cc: Nikita Kiryanov <[email protected]>
Cc: Paul Kocialkowski <[email protected]>
Cc: Enric Balletbo i Serra <[email protected]>
Cc: Adam Ford <[email protected]>
Cc: Steve Sakoman <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Thomas Weber <[email protected]>
Cc: Hannes Schmelzer <[email protected]>
Cc: Thomas Chou <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Joe Hershberger <[email protected]>
Cc: Sam Protsenko <[email protected]>
Cc: Heiko Schocher <[email protected]>
Cc: Samuel Egli <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Wolfgang Denk <[email protected]>
Cc: Mateusz Kulikowski <[email protected]>
Cc: Ben Whitten <[email protected]>
Cc: Stefano Babic <[email protected]>
Cc: Bin Meng <[email protected]>
Cc: Sekhar Nori <[email protected]>
Cc: Mugunthan V N <[email protected]>
Cc: "B, Ravi" <[email protected]>
Cc: "Matwey V. Kornilov" <[email protected]>
Cc: Ladislav Michl <[email protected]>
Cc: Ash Charles <[email protected]>
Cc: "Kipisz, Steven" <[email protected]>
Cc: Daniel Allred <[email protected]>
Signed-off-by: Tom Rini <[email protected]>
Tested-by: Lokesh Vutla <[email protected]>
Acked-by: Lokesh Vutla <[email protected]>
Tested-by: Ladislav Michl <[email protected]>