Make lcov.sh run from the build directory

lcov.sh can now be called from any build directory and
also still works with in-place builds too.

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/scripts/lcov.sh b/scripts/lcov.sh
index 9e52b98..2cf566a 100755
--- a/scripts/lcov.sh
+++ b/scripts/lcov.sh
@@ -43,8 +43,8 @@
 set -eu
 
 # Repository detection
-in_mbedtls_repo () {
-     test -d include -a -d library -a -d programs -a -d tests
+in_mbedtls_build_dir () {
+     test -d library
  }
 
 # Collect stats and build a HTML report.
@@ -74,11 +74,11 @@
     exit
 fi
 
-if in_mbedtls_repo; then
+if in_mbedtls_build_dir; then
     library_dir='library'
     title='Mbed TLS'
 else
-    library_dir='build/core'
+    library_dir='core'
     title='TF-PSA-Crypto'
 fi