lib_manager: Add cache writeback after library loading to IMR

Add dcache_writeback_region() call after copying library data to IMR
(Isolated Memory Region) to ensure cache coherency in multicore
scenarios.

Without this cache operation, when Core 0 loads a library into IMR via
memcpy_s(), the data remains in Core 0's data cache and is not written
back to main memory. When Core 1 later tries to create a module from
this library, it reads uninitialized or stale data from IMR, causing
either:
- "Unsupported module API version" errors (reading garbage build info)
- Fatal PIF data errors and crashes (accessing corrupted module data)

The fix adds a single cache writeback operation after all library data
(manifest + module code/data) has been copied to IMR. This ensures
library data written by Core 0 is flushed from cache to IMR memory
before Core 1 attempts to read it, following the standard cache
coherency protocol for non-coherent Harvard architecture (Xtensa).

Fixes multicore topology crashes on Intel MTL, LNL, PTL, NVL platforms
when loading external libraries with modules instantiated on secondary
cores.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

src/library_manager/lib_manager.c

@@ -937,6 +937,9 @@ static int lib_manager_store_library(struct lib_manager_dma_ext *dma_ext,
 		return ret;
 	}
 
+	/* Writeback entire library to ensure it's visible to other cores */
+	dcache_writeback_region((__sparse_force void *)library_base_address, preload_size);
+
 #if CONFIG_LIBRARY_AUTH_SUPPORT
 	/* AUTH_PHASE_LAST - do final library authentication checks */
 	ret = lib_manager_auth_proc((__sparse_force void *)library_base_address,