nyan: Use asm volatile instead of plain asm so it doesn't get optimized out.

If an asm blob isn't marked as volatile, gcc is free to throw it out if it
doesn't think it produces any values that are actually used. To prevent that
from happening, add volatile to some asm blobs in the nyan romstage code.

BUG=None
TEST=Booted on nyan rev1.
BRANCH=None

Original-Change-Id: I819e068e738e94ea749fcb72bba2eee080e1dfb1
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/185610
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 76c09581d6ca4dc6c2f9048f599822939f439d11)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I0b32197abf0ddc5f454f9c2415a65d98c60ca48b
Reviewed-on: http://review.coreboot.org/7396
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
tegra124: nyan: Keep in memory structures below 4GB.

We'd been putting some data structures like the framebuffer and the cbmem at
the end of memory, but that may not actually be addressable as identity mapped
memory. This change clamps the addresses those structures are placed at so
they stay below 4GB.

BUG=None
TEST=Booted on nyan. Went into recovery mode and verified that there was a
recovery screen. Forced memory size to be 4GB and verified that the recovery
screen still shows up.
BRANCH=None

Original-Change-Id: I9e6b28212c113107d4f480b3dd846dd2349b3a91
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/185571
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 63ea1274a838dc739d302d7551f1db42034c5bd0)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I970c1285270cb648bc67fa114d44c0841eab1615
Reviewed-on: http://review.coreboot.org/7397
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)