Replace all SCP FW (BL0, BL3-0) references

This patch replaces all references to the SCP Firmware (BL0, BL30,
BL3-0, bl30) with the image terminology detailed in the TF wiki
(https://github.com/ARM-software/arm-trusted-firmware/wiki):

    BL0          -->  SCP_BL1
    BL30, BL3-0  -->  SCP_BL2
    bl30         -->  scp_bl2

This change affects code, documentation, build system, tools and
platform ports that load SCP firmware. ARM plaforms have been
updated to the new porting API.

IMPORTANT: build option to specify the SCP FW image has changed:

    BL30 --> SCP_BL2

IMPORTANT: This patch breaks compatibility for platforms that use BL2
to load SCP firmware. Affected platforms must be updated as follows:

    BL30_IMAGE_ID --> SCP_BL2_IMAGE_ID
    BL30_BASE --> SCP_BL2_BASE
    bl2_plat_get_bl30_meminfo() --> bl2_plat_get_scp_bl2_meminfo()
    bl2_plat_handle_bl30() --> bl2_plat_handle_scp_bl2()

Change-Id: I24c4c1a4f0e4b9f17c9e4929da815c4069549e58
diff --git a/drivers/auth/tbbr/tbbr_cot.c b/drivers/auth/tbbr/tbbr_cot.c
index ab0243d..6023c78 100644
--- a/drivers/auth/tbbr/tbbr_cot.c
+++ b/drivers/auth/tbbr/tbbr_cot.c
@@ -230,8 +230,8 @@
 			}
 		}
 	},
-	[BL30_IMAGE_ID] = {
-		.img_id = BL30_IMAGE_ID,
+	[SCP_BL2_IMAGE_ID] = {
+		.img_id = SCP_BL2_IMAGE_ID,
 		.img_type = IMG_RAW,
 		.parent = &cot_desc[SCP_FW_CONTENT_CERT_ID],
 		.img_auth_methods = {