ARC: reuse headers for both ARCv3 and ARCv3 if possible

Reuse ARCv2 headers [where it is possible] for ARCv3.
In this commit we simply allow to use them for ARCv3, we'll
move it to proper folder and rename them [where it is required]
in the upcoming cleanup patch.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>

arch/arc/include/kernel_arch_func.h

@@ -24,9 +24,7 @@
 
 #include <kernel_arch_data.h>
 
-#ifdef CONFIG_ISA_ARCV2
 #include <v2/irq.h>
-#endif
 
 #ifdef __cplusplus
 extern "C" {

include/arch/arc/arch.h

@@ -23,15 +23,16 @@
 #include <arch/common/sys_bitops.h>
 #include "sys-io-common.h"
 
-#ifdef CONFIG_ISA_ARCV2
 #include <arch/arc/v2/exc.h>
 #include <arch/arc/v2/irq.h>
-#include <arch/arc/v2/error.h>
 #include <arch/arc/v2/misc.h>
 #include <arch/arc/v2/aux_regs.h>
 #include <arch/arc/v2/arcv2_irq_unit.h>
 #include <arch/arc/v2/asm_inline.h>
 #include <arch/common/addr_types.h>
+#include <arch/arc/v2/error.h>
+
+#ifdef CONFIG_ISA_ARCV2
 #include "v2/sys_io.h"
 #ifdef CONFIG_ARC_CONNECT
 #include <arch/arc/v2/arc_connect.h>

include/arch/arc/arch_inlines.h

@@ -12,9 +12,7 @@
 
 #include <kernel_structs.h>
 
-#ifdef CONFIG_ISA_ARCV2
 #include <arch/arc/v2/aux_regs.h>
-#endif
 
 static ALWAYS_INLINE _cpu_t *arch_curr_cpu(void)
 {