arm-bsp/ssh-pregen-hostkeys: fix corstone1000 typo

Signed-off-by: Ross Burton <ross.burton@arm.com>

meta-arm-bsp/recipes-connectivity/ssh-pregen-hostkeys/ssh-pregen-hostkeys_%.bbappend

@@ -1,6 +1,6 @@
 # These machines cannot run in product as they are virtual
 # platforms, so allow ssh-pregen-hostkeys to be used.
 
-COMPATIBLE_MACHINE:corestone1000-fvp = "corestone1000-fvp"
+COMPATIBLE_MACHINE:corstone1000-fvp = "corstone1000-fvp"
 COMPATIBLE_MACHINE:fvp-base = "fvp-base"
 COMPATIBLE_MACHINE:sbsa-ref = "sbsa-ref"