ARC: show_regs: fix r12 printing and simplify

ARC: show_regs: fix r12 printing and simplify

[ Upstream commit e5c388b4b967037a0e00b60194b0dbcf94881a9b ]

when working on ARC64, spotted an issue in ARCv2 reg file printing.
print_reg_file() assumes contiguous reg-file whereas in ARCv2 they are
not: r12 comes before r0-r11 due to hardware auto-save. Apparently this
issue has been present since v2 port submission.

To avoid bolting hacks for this discontinuity while looping through
pt_regs, just ditching the loop and print pt_regs directly.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>