sh: process: Fix broken lines in register dumps

Rejoin the broken lines by using pr_cont().
Convert the remaining printk() calls to pr_*() while at it.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rich Felker <dalias@libc.org>