usb: gadget: g_dnl: add function g_dnl_set_product

Add a function g_dnl_set_product to change the Product string used in USB
enumeration in any command based on download gadget.

If the function is called with NULL pointer, the product string is set to
the default value (product[] = "USB download gadget").

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
2 files changed