soc: aspeed: lpc-snoop: Consolidate channel initialisation

soc: aspeed: lpc-snoop: Consolidate channel initialisation

Previously, channel initialisation was a bit perilous with respect to
resource cleanup in error paths. While the implementation had issues,
it at least made an effort to eliminate some of its problems by first
testing whether any channels were enabled, and bailing out if not.

Having improved the robustness of resource handling in probe() we can
now rearrange the initial channel test to be located with the subsequent
test, and rework the unrolled conditional logic to use a loop for an
improvement in readability.

Link: https://patch.msgid.link/20250616-aspeed-lpc-snoop-fixes-v2-9-3cdd59c934d3@codeconstruct.com.au
Acked-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>