Move the inclusion of crypto_spe.h to psa/crypto_platform.h

This makes it easier to ensure that crypto_spe.h is included everywhere it
needs to be, and that it's included early enough to do its job (it must be
included before any mention of psa_xxx() functions with external linkage,
because it defines macros to rename these functions).

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/spm_build.txt b/ChangeLog.d/spm_build.txt
new file mode 100644
index 0000000..6016d84
--- /dev/null
+++ b/ChangeLog.d/spm_build.txt
@@ -0,0 +1,4 @@
+Bugfix
+   * When MBEDTLS_PSA_CRYPTO_SPM is enabled, crypto_spe.h was not included
+     in all the right places. Include it from crypto_platform.h, which is
+     the natural place. Fixes #4649.