code_relocation: fix ruff B028 warnings

The ruff python linter produces a B028 warning when the warnings.warn()
function is called with a stacklevel parameter.

By default the function will set a stacklevel of 1 which causes it to
output the stack frame of the line where the function is called without
any context information from higher up the stack.

It is recommended to use a stacklevel of 2 or higher. Therfore, this patch
sets the stacklevel parameter of all warnings.warn() calls to to 2.

Signed-off-by: Joel Holdsworth <jholdsworth@nvidia.com>