remoteproc: imx_rproc: Fix invalid loaded resource table detection

In the Linux kernel, the following vulnerability has been resolved:

remoteproc: imx_rproc: Fix invalid loaded resource table detection

imx_rproc_elf_find_loaded_rsc_table() may incorrectly report a loaded

resource table even when the current firmware does not provide one.

When the device tree contains a "rsc-table" entry, priv->rsc_table is

non-NULL and denotes where a resource table would be located if one is

present in memory. However, when the current firmware has no resource

table, rproc->table_ptr is NULL. The function still returns

priv->rsc_table, and the remoteproc core interprets this as a valid loaded

resource table.

Fix this by returning NULL from imx_rproc_elf_find_loaded_rsc_table() when

there is no resource table for the current firmware (i.e. when

rproc->table_ptr is NULL). This aligns the function's semantics with the

remoteproc core: a loaded resource table is only reported when a valid

table_ptr exists.

With this change, starting firmware without a resource table no longer

triggers a crash.