bsp: Rename corstone1000-image

As we intend to build 2 Corstone-1000 disk images, one for the firmware
in flash and an external mass storage image the existing
corstone1000-image.bb file has been renamed to
corstone1000-flash-firmware-image.bb to make it clear what it's for.
The wks file for specifing the image layout has also been renamed to
make its purpose clearer.

Signed-off-by: Drew Reed <Drew.Reed@arm.com>

ci/corstone1000-common.yml

@@ -38,5 +38,5 @@ local_conf_header:
     IMAGE_INSTALL += "packagegroup-ts-tests-psa"
 
 target:
-  - corstone1000-image
+  - corstone1000-flash-firmware-image
   - perf

meta-arm-bsp/conf/machine/include/corstone1000.inc

@@ -44,7 +44,7 @@ MACHINE_FEATURES += "arm-ffa"
 # login terminal serial port settings
 SERIAL_CONSOLES ?= "115200;ttyAMA0"
 
-WKS_FILE ?= "corstone1000-image.corstone1000.wks"
+WKS_FILE ?= "corstone1000-flash-firmware.wks.in"
 
 # making sure EXTRA_IMAGEDEPENDS will be used while creating the image
 WKS_FILE_DEPENDS:append = " ${EXTRA_IMAGEDEPENDS}"