fastboot: Change fastboot_buf_addr to an address

Given the name of this variable, it should be an address, not a
pointer. Update this, to make it easier to use with sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Dmitrii Merkurev <dimorinny@google.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # on vim3
5 files changed