remoteproc: Fix potential build issues with SPL remoteproc

The rproc uclass driver can either be built with SPL_REMOTEPROC
or REMOTEPROC, but the function prototypes in remoteproc.h are
defined only when CONFIG_REMOTEPROC is defined. This can cause
build issues in SPL if CONFIG_REMOTEPROC is not selected.

Fix this by replacing the existing precompiler macro usage with
CONFIG_IS_ENABLED.

Fixes: ddf56bc7 ("drivers: Introduce a simplified remoteproc framework")
Signed-off-by: NSuman Anna <s-anna@ti.com>
Reviewed-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NLokesh Vutla <lokeshvutla@ti.com>

include/remoteproc.h

@@ -130,7 +130,7 @@ struct dm_rproc_ops {
 /* Accessor */
 #define rproc_get_ops(dev) ((struct dm_rproc_ops *)(dev)->driver->ops)
 
-#ifdef CONFIG_REMOTEPROC
+#if CONFIG_IS_ENABLED(REMOTEPROC)
 /**
  * rproc_init() - Initialize all bound remote proc devices
  * @return 0 if all ok, else appropriate error value.