cmd/sbi: add missing SBI information

Let the sbi command display:

* machine vendor ID
* machine architecture ID
* machine implementation ID

With this patch the output for the HiFive Unmatched looks like

    => sbi
    SBI 0.3
    OpenSBI 0.9
    Machine:
      Vendor ID 489
      Architecture ID 8000000000000007
      Implementation ID 20181004
    Extensions:
      sbi_set_timer
      sbi_console_putchar
      sbi_console_getchar
      sbi_clear_ipi
      sbi_send_ipi
      sbi_remote_fence_i
      sbi_remote_sfence_vma
      sbi_remote_sfence_vma_asid
      sbi_shutdown
      SBI Base Functionality
      Timer Extension
      IPI Extension
      RFENCE Extension
      Hart State Management Extension
      System Reset Extension

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/cmd/riscv/sbi.c b/cmd/riscv/sbi.c
index 8349123..8fc8ab0 100644
--- a/cmd/riscv/sbi.c
+++ b/cmd/riscv/sbi.c
@@ -52,6 +52,7 @@
 {
 	int i, impl_id;
 	long ret;
+	long mvendorid, marchid, mimpid;
 
 	ret = sbi_get_spec_version();
 	if (ret >= 0)
@@ -77,7 +78,17 @@
 		if (i == ARRAY_SIZE(implementations))
 			printf("Unknown implementation ID %ld", ret);
 	}
-	printf("\nExtensions:\n");
+	printf("\nMachine:\n");
+	ret = sbi_get_mvendorid(&mvendorid);
+	if (!ret)
+		printf("  Vendor ID %lx\n", mvendorid);
+	ret = sbi_get_marchid(&marchid);
+	if (!ret)
+		printf("  Architecture ID %lx\n", marchid);
+	ret = sbi_get_mimpid(&mimpid);
+	if (!ret)
+		printf("  Implementation ID %lx\n", mimpid);
+	printf("Extensions:\n");
 	for (i = 0; i < ARRAY_SIZE(extensions); ++i) {
 		ret = sbi_probe_extension(extensions[i].id);
 		if (ret > 0)