ARC: switch to generic ENTRY/END assembler annotations

With commit 9df62f0544 "arch: use ASM_NL instead of ';'" the generic
macros can handle the arch specific newline quirk. Hence we can get rid
of ARC asm macros and use the "C" style macros.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/kernel/ctx_sw_asm.S

@@ -62,4 +62,4 @@ __switch_to:
 	ld.ab   blink, [sp, 4]
 	j       [blink]
 
-ARC_EXIT __switch_to
+END(__switch_to)