arm/trusted-firmware-a: rename to 2.7.0 to match upstream

The upstream version is 2.7.0, so use that name instead of just 2.7.

Also remove the unversioned bbappend which simply extended
FILESEXTRAPATHS, there's no need for this split now that we aim to have
~1 version of TF-A in the tree.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/recipes-bsp/trusted-firmware-a/trusted-firmware-a_2.%.bbappend

@@ -1,3 +0,0 @@
-FILESEXTRAPATHS:prepend := "${THISDIR}/files/:"
-
-# Don't put machine customisation in here, use a versioned append.

meta-arm-bsp/recipes-bsp/trusted-firmware-a/trusted-firmware-a_2.7.%.bbappend

@@ -1,3 +1,5 @@
+FILESEXTRAPATHS:prepend := "${THISDIR}/files/:"
+
 # Machine specific TFAs
 
 MACHINE_TFA_REQUIRE ?= ""