sysinfo, procfs: Support memory info partially

Change-Id: I597dae4f82d64d3f23889cef960db18ae879ff06
refs: #1389

kernel/include/syscall.h

@@ -443,6 +443,22 @@ struct rusage {
 	long   ru_nivcsw;
 };
 
+struct sysinfo {
+	long uptime;             /* Seconds since boot */
+	unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
+	unsigned long totalram;  /* Total usable main memory size */
+	unsigned long freeram;   /* Available memory size */
+	unsigned long sharedram; /* Amount of shared memory */
+	unsigned long bufferram; /* Memory used by buffers */
+	unsigned long totalswap; /* Total swap space size */
+	unsigned long freeswap;  /* swap space still available */
+	unsigned short procs;    /* Number of current processes */
+	unsigned long totalhigh; /* Total high memory size */
+	unsigned long freehigh;  /* Available high memory size */
+	unsigned int mem_unit;   /* Memory unit size in bytes */
+	char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding for libc5 */
+};
+
 extern void terminate(int, int);
 
 struct tod_data_s {