fix(st): fix NULL pointer dereference issues

The get_bl_mem_params_node() function could return NULL. Add asserts to
check the return value is not NULL.
This corrects coverity issues:
	pager_mem_params = get_bl_mem_params_node(BL32_EXTRA1_IMAGE_ID);
>>>     CID 378360:    (NULL_RETURNS)
>>>     Dereferencing "pager_mem_params", which is known to be "NULL".

	paged_mem_params = get_bl_mem_params_node(BL32_EXTRA2_IMAGE_ID);
>>>     CID 378360:    (NULL_RETURNS)
>>>     Dereferencing "paged_mem_params", which is known to be "NULL".

	tos_fw_mem_params = get_bl_mem_params_node(TOS_FW_CONFIG_ID);
>>>     CID 378360:    (NULL_RETURNS)
>>>     Dereferencing "tos_fw_mem_params", which is known to be "NULL".


Do the same for other occurrences of get_bl_mem_params_node() return not
checked, in the functions plat_get_bl_image_load_info() and
bl2_plat_handle_pre_image_load().

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I79165b1628fcee3da330f2db4ee5e1dafcb1b21f
3 files changed