Revert optimisations related to preemptable SPM in Library mode

This patch needs deeper testing on other platforms as the nightly
regression discovers issues that the CI does not cover. Better
revert it for the time being.

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I4b9fa788740ccb5480cd5e934fedebea338941cf
diff --git a/secure_fw/spm/include/tfm_arch.h b/secure_fw/spm/include/tfm_arch.h
index 8a96d9f..f9b7a3d 100644
--- a/secure_fw/spm/include/tfm_arch.h
+++ b/secure_fw/spm/include/tfm_arch.h
@@ -36,7 +36,7 @@
     uint32_t    lr;
     uint32_t    ra;
     uint32_t    xpsr;
-} __attribute__ ((aligned(8)));
+};
 
 #define TFM_STATE_RET_VAL(ctx) (((struct tfm_state_context_t *)((ctx)->sp))->r0)