pinctrl: aspeed: Improve debug output

We need to iterate over each pin in a group for a function and
disable higher priority mux configurations on the pin before finally
muxing the relevant function's signal. With the current debug output it
is hard to track what register output is relevant to which operation, so
break up the actions in the debug output by providing some more context.

Before:

    [    5.446656] aspeed-g6-pinctrl 1e6e2000.syscon:pinctrl: request pin 37 (B26) for 1e780000.gpio:341
    [    5.447377] Want SCU414[0x00000020]=0x1, got 0x0 from 0x00000000
    [    5.447854] Want SCU4B4[0x00000020]=0x1, got 0x0 from 0x00000000
    [    5.448340] Want SCU4B4[0x00000020]=0x1, got 0x0 from 0x00000000

After:

    [    5.298053] Muxing pin 37 for GPIO
    [    5.298294] Disabling signal NRI4 for NRI4
    [    5.298593] Want SCU414[0x00000020]=0x1, got 0x0 from 0x00000000
    [    5.298983] Disabling signal RGMII4RXD1 for RGMII4
    [    5.299309] Want SCU4B4[0x00000020]=0x1, got 0x0 from 0x00000000
    [    5.299694] Disabling signal RMII4RXD1 for RMII4
    [    5.300014] Want SCU4B4[0x00000020]=0x1, got 0x0 from 0x00000000
    [    5.300396] Enabling signal GPIOE5 for GPIOE5
    [    5.300687] Muxed pin 37 as GPIOE5

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20200701030039.2834418-1-joel@jms.id.au


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>