ARM: keystone: Move CPU bringup code to dedicated asm file

Because of inline asm usage in platsmp.c, smc instruction
creates build failure for ARM V6+V7 build where as using instruction
encoding for smc breaks the thumb2 build.

So move the code snippet to separate asm file and mark
it with 'armv7-a$(plus_sec)' to avoid any build issues.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/mach-keystone/platsmp.c b/arch/arm/mach-keystone/platsmp.c
index 630ab3b..1d4181e 100644
--- a/arch/arm/mach-keystone/platsmp.c
+++ b/arch/arm/mach-keystone/platsmp.c
@@ -30,18 +30,9 @@
 	pr_debug("keystone-smp: booting cpu %d, vector %08lx\n",
 		 cpu, start);
 
-	asm volatile (
-		"mov    r0, #0\n"	/* power on cmd	*/
-		"mov    r1, %1\n"	/* cpu		*/
-		"mov    r2, %2\n"	/* start	*/
-		".inst  0xe1600070\n"	/* smc #0	*/
-		"mov    %0, r0\n"
-		: "=r" (error)
-		: "r"(cpu), "r"(start)
-		: "cc", "r0", "r1", "r2", "memory"
-	);
-
-	pr_debug("keystone-smp: monitor returned %d\n", error);
+	error = keystone_cpu_smc(KEYSTONE_MON_CPU_UP_IDX, cpu, start);
+	if (error)
+		pr_err("CPU %d bringup failed with %d\n", cpu, error);
 
 	return error;
 }