feat(fdt-wrappers): add function to read uint64 with default value

Adds a new utility function fdt_read_uint64_default() to read a uint64
value with a default value, as it is already done for uint32.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Signed-off-by: Maxime Méré <maxime.mere@foss.st.com>
Change-Id: Ibc85e30c3e4dd4b5171bdec106f4e32eb78c579f
2 files changed