Remove dashes from image names: 'BL3-x' --> 'BL3x'

This patch removes the dash character from the image name, to
follow the image terminology in the Trusted Firmware Wiki page:

    https://github.com/ARM-software/arm-trusted-firmware/wiki

Changes apply to output messages, comments and documentation.

non-ARM platform files have been left unmodified.

Change-Id: Ic2a99be4ed929d52afbeb27ac765ceffce46ed76
diff --git a/make_helpers/tbbr/tbbr_tools.mk b/make_helpers/tbbr/tbbr_tools.mk
index 9b47886..e934d72 100644
--- a/make_helpers/tbbr/tbbr_tools.mk
+++ b/make_helpers/tbbr/tbbr_tools.mk
@@ -35,7 +35,7 @@
 # Expected environment:
 #
 #   BUILD_PLAT: output directory
-#   NEED_BL32: indicates whether BL3-2 is needed by the platform
+#   NEED_BL32: indicates whether BL32 is needed by the platform
 #   BL2: image filename (optional). Default is IMG_BIN(2) (see macro IMG_BIN)
 #   SCP_BL2: image filename (optional). Default is IMG_BIN(30)
 #   BL31: image filename (optional). Default is IMG_BIN(31)