lib: nrf_modem_lib: Add missing comma in assert

The recently added assert statement was missing comma.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

lib/nrf_modem_lib/nrf_modem_os_rpc.c

@@ -19,7 +19,7 @@
 #include <zephyr/ipc/pbuf.h>
 
 #define DCACHE_LINE_SIZE (CONFIG_DCACHE_LINE_SIZE)
-BUILD_ASSERT(DCACHE_LINE_SIZE == 32
+BUILD_ASSERT(DCACHE_LINE_SIZE == 32,
 	     "Unexpected data cache line size " STRINGIFY(DCACHE_LINE_SIZE) ", expected 32");
 
 /** Structure to hold pbuf configuration and data. */