Fix "unterminated '#pragma clang attribute push'" in sha256/sha512.c

If we're built with MBEDTLS_SHAxxx_USE_A64_CRYPTO_IF_PRESENT but don't have a
way to detect the crypto extensions required, the code turns off _IF_PRESENT
and falls back to C only (with a warning). This was done after the attributes
are pushed, and the pop is done only #if defined(xxx_IF_PRESENT), so this
commit fixes that.

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/sha256.c b/library/sha256.c
index 08822f4..169229c 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -399,6 +399,8 @@
             SHA256_BLOCK_SIZE) ? 0 : -1;
 }
 
+#endif /* MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT || MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY */
+
 #if defined(MBEDTLS_POP_TARGET_PRAGMA)
 #if defined(__clang__)
 #pragma clang attribute pop
@@ -408,8 +410,6 @@
 #undef MBEDTLS_POP_TARGET_PRAGMA
 #endif
 
-#endif /* MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT || MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY */
-
 #if !defined(MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT)
 #define mbedtls_internal_sha256_process_many_c mbedtls_internal_sha256_process_many
 #define mbedtls_internal_sha256_process_c      mbedtls_internal_sha256_process
diff --git a/library/sha512.c b/library/sha512.c
index 67acfee..b8b2485 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -569,6 +569,8 @@
             SHA512_BLOCK_SIZE) ? 0 : -1;
 }
 
+#endif /* MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT || MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY */
+
 #if defined(MBEDTLS_POP_TARGET_PRAGMA)
 #if defined(__clang__)
 #pragma clang attribute pop
@@ -578,8 +580,6 @@
 #undef MBEDTLS_POP_TARGET_PRAGMA
 #endif
 
-#endif /* MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT || MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY */
-
 
 #if !defined(MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT)
 #define mbedtls_internal_sha512_process_many_c mbedtls_internal_sha512_process_many