Crypto: Refine how crypto modules are selected

Crypto modules can be only enable/disable by setting the
CRYPTO_XXX_MODULE_DISABLED to 0/1.
This patch refines how the modules are selected. With this patch,
the crypto modules can be enabled/disabled by setting the
CRYPTO_XXX_MODULE_DISABLED to 0/1, OFF/ON or FALSE/TRUE, not
limited to 0/1 anymore.

Change-Id: I4f5ea82805760883639950cd6031cbf658cb0bfc
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/secure_fw/services/crypto/crypto_asymmetric.c b/secure_fw/services/crypto/crypto_asymmetric.c
index 78932ea..bfca546 100644
--- a/secure_fw/services/crypto/crypto_asymmetric.c
+++ b/secure_fw/services/crypto/crypto_asymmetric.c
@@ -29,7 +29,7 @@
                                         psa_outvec out_vec[],
                                         size_t out_len)
 {
-#if (TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED != 0)
+#ifdef TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED
     return PSA_ERROR_NOT_SUPPORTED;
 #else
     if ((in_len != 2) || (out_len != 1)) {
@@ -63,7 +63,7 @@
                                           psa_outvec out_vec[],
                                           size_t out_len)
 {
-#if (TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED != 0)
+#ifdef TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED
     return PSA_ERROR_NOT_SUPPORTED;
 #else
     if ((in_len != 3) || (out_len != 0)) {
@@ -97,7 +97,7 @@
                                            psa_outvec out_vec[],
                                            size_t out_len)
 {
-#if (TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED != 0)
+#ifdef TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED
     return PSA_ERROR_NOT_SUPPORTED;
 #else
     psa_status_t status;
@@ -153,7 +153,7 @@
                                            psa_outvec out_vec[],
                                            size_t out_len)
 {
-#if (TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED != 0)
+#ifdef TFM_CRYPTO_ASYMMETRIC_MODULE_DISABLED
     return PSA_ERROR_NOT_SUPPORTED;
 #else
     if (!((in_len == 2) || (in_len == 3)) || (out_len != 1)) {