tc: use common tc code for tftf

TFTF was refactored to share common code between tc platforms.
Therefore instead of using tc0 as the platform it is now tc.
This patch modifies the tc configs to reflect this.

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: If35e138018b5bcc168430f195c9b0eab6cf561ad
diff --git a/tftf_config/fvp-tc-spm b/tftf_config/fvp-tc-spm
new file mode 100644
index 0000000..439ad9a
--- /dev/null
+++ b/tftf_config/fvp-tc-spm
@@ -0,0 +1,3 @@
+CROSS_COMPILE=aarch64-none-elf-
+PLAT=tc
+TESTS=spm