refactor(measured-boot): change all occurrences of RSS to RSE

Changes all occurrences of "RSS" and "rss" in the code and build files
to "RSE" and "rse".

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I8c2fcbdf1de1c75f9969d28bc15e0b3500071404
diff --git a/drivers/measured_boot/rse/dice_prot_env.mk b/drivers/measured_boot/rse/dice_prot_env.mk
index c5a35e0..7c83307 100644
--- a/drivers/measured_boot/rse/dice_prot_env.mk
+++ b/drivers/measured_boot/rse/dice_prot_env.mk
@@ -26,4 +26,4 @@
         DPE_DIGEST_SIZE \
 )))
 
-DPE_SOURCES	+=	drivers/measured_boot/rss/dice_prot_env.c
+DPE_SOURCES	+=	drivers/measured_boot/rse/dice_prot_env.c