SST: Update integration guide for SST service

This patch updates the SST integration guide to
replace the memory mapped flash implementation by
the new flash implementation based on CMSIS flash
driver.

Change-Id: Iefe0acb27c09f4af1ba846bebb0e064aee7bec63
Signed-off-by: Marc Moreno <marc.morenoberengue@arm.com>
1 file changed