Rename *KEYPAIR* to *KEY_PAIR*

Be consistent with PUBLIC_KEY.

perl -i -pe 's/KEYPAIR/KEY_PAIR/g' $(git ls-files)
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index a23487b..8064be5 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -81,7 +81,7 @@
     psa_key_handle_t key;
 
     const int curve = PSA_ECC_CURVE_SECP256R1;
-    const psa_key_type_t type = PSA_KEY_TYPE_ECC_KEYPAIR(curve);
+    const psa_key_type_t type = PSA_KEY_TYPE_ECC_KEY_PAIR(curve);
     const size_t bits = 256;
     psa_key_policy_t policy;