ARM: dts: aspeed: Drop "fsi-master" compatibles

ARM: dts: aspeed: Drop "fsi-master" compatibles

The "fsi-master" compatible has been used inconsistently on FSI masters.
It doesn't have any real use or meaning, so it's easier to drop it
everywhere than add it where missing. It is also not documented by any
schemas (only .txt bindings).

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Eddie James <eajames@linux.ibm.com>
Link: https://patch.msgid.link/20250731-dt-fsi-cleanups-v1-2-e7b695a29fc3@kernel.org
[arj: Drop hunk affecting removed swift platform]
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>