fsp2: move to 4.17.18

Bump the linux kernel version to 4.17.18 which includes
fix for the secuirity vulnerability in #3359.

Signed-off-by: Ivan Mikhaylov <ivan@de.ibm.com>
Change-Id: Ia09a7baada1a78a3e6b1186fe6fa015344db6048
3 files changed