target/arc: allow reading memory while target runs

target/arc: allow reading memory while target runs

There is no reason that ARC can't support reading from memory over JTAG
while the target is executing, and this is in fact required for RTT
support. Remove this check from arc_mem_read and arc_mem_write

Change-Id: I2accfb4b99bf77c5473d133623e0eb0632cb45f6
Signed-off-by: Daniel DeGrasse <ddegrasse@tenstorrent.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8721
Tested-by: jenkins
Reviewed-by: Evgeniy Didin <didin@synopsys.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>