ARM: adjust arm-smccc code for use in U-Boot

Adjust ARM SMC Calling Convention code for U-Boot:
  - Replace the license block with SPDX
  - Change path to asm-offsets.h
  - Define UNWIND() as no-op
  - Add Kconfig entry
  - Add asm-offsets

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/lib/asm-offsets.c b/arch/arm/lib/asm-offsets.c
index e5bcaea..d620dc0 100644
--- a/arch/arm/lib/asm-offsets.c
+++ b/arch/arm/lib/asm-offsets.c
@@ -14,6 +14,7 @@
 
 #include <common.h>
 #include <linux/kbuild.h>
+#include <linux/arm-smccc.h>
 
 #if defined(CONFIG_MX25) || defined(CONFIG_MX27) || defined(CONFIG_MX35) \
 	|| defined(CONFIG_MX51) || defined(CONFIG_MX53)
@@ -198,5 +199,12 @@
 	DEFINE(PLL_DP_HFS_MFN, offsetof(struct dpll, dp_hfs_mfn));
 #endif
 
+#ifdef CONFIG_ARM_SMCCC
+	DEFINE(ARM_SMCCC_RES_X0_OFFS, offsetof(struct arm_smccc_res, a0));
+	DEFINE(ARM_SMCCC_RES_X2_OFFS, offsetof(struct arm_smccc_res, a2));
+	DEFINE(ARM_SMCCC_QUIRK_ID_OFFS, offsetof(struct arm_smccc_quirk, id));
+	DEFINE(ARM_SMCCC_QUIRK_STATE_OFFS, offsetof(struct arm_smccc_quirk, state));
+#endif
+
 	return 0;
 }