MIPS: TXx9: Modernize printing of kernel messages

- Convert from printk() to pr_*(),
  - Add missing continuations, to fix user-visible breakage,
  - Drop superfluous casts (u64 has been unsigned long long on all
    architectures for many years).

On rbtx4927, this restores the kernel output like:

    -TX4927 SDRAMC --
    - CR0:0000007e00000544
    - TR:32800030e
    +TX4927 SDRAMC -- CR0:0000007e00000544 TR:32800030e

and:

    -PCIC -- PCICLK:
    -Internal(33.3MHz)
    -
    +PCIC -- PCICLK:Internal(33.3MHz)

Fixes: 4bcc595c ("printk: reinstate KERN_CONT for printing continuation lines")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14646/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>