gpu: nova: require little endian

The driver already assumes little endian in a lot of locations. For
example, all the code that reads RPCs out of the command queue just
directly interprets the bytes.

Make this explicit in Kconfig.

Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: https://patch.msgid.link/20260407-fix-kconfig-v2-1-6b4fb06c690c@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

drivers/gpu/drm/nova/Kconfig

@@ -4,6 +4,7 @@ config DRM_NOVA
 	depends on DRM=y
 	depends on PCI
 	depends on RUST
+	depends on !CPU_BIG_ENDIAN
 	select AUXILIARY_BUS
 	select NOVA_CORE
 	default n

drivers/gpu/nova-core/Kconfig

@@ -3,6 +3,7 @@ config NOVA_CORE
 	depends on 64BIT
 	depends on PCI
 	depends on RUST
+	depends on !CPU_BIG_ENDIAN
 	select AUXILIARY_BUS
 	select RUST_FW_LOADER_ABSTRACTIONS
 	default n