efi_loader: Prevent free of uninitialised pointer

efi_loader: Prevent free of uninitialised pointer

Taking a goto to out_of_resources before receive_lengths is assigned
will result in an attempt to free an unitialised pointer. Instead
initialise receive_lengths to NULL on declaration to prevent this from
occurring.

This issue was found by Smatch.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>