remoteproc: use SIZE_MAX in rproc_u64_fit_in_size_t()

Smatch reports:

drivers/remoteproc/remoteproc_elf_loader.c:221
warn: always true condition '(val <= -1)'

The helper function rproc_u64_fit_in_size_t() compares the value
against (size_t)-1, which is equivalent to SIZE_MAX but can confuse
static analysis tools and lead to the above warning.

Replace (size_t)-1 with SIZE_MAX to make the intent explicit and
avoid the Smatch warning without changing the behavior.

Signed-off-by: Anas Iqbal <mohd.abd.6602@gmail.com>
Link: https://lore.kernel.org/r/20260314110137.178981-1-mohd.abd.6602@gmail.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: iqbalcodes6602

drivers/remoteproc/remoteproc_internal.h

@@ -218,7 +218,7 @@ bool rproc_u64_fit_in_size_t(u64 val)
 	if (sizeof(size_t) == sizeof(u64))
 		return true;
 
-	return (val <= (size_t) -1);
+	return val <= SIZE_MAX;
 }
 
 #endif /* REMOTEPROC_INTERNAL_H */