ARC: switch to generic ENTRY/END assembler annotations

With commit 9df62f05 "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>