Dump /proc/bootconfig in dumpstate

These bootconfig arguments were previously in the kernel cmdline, so we
now dump the contents next to the kernel cmdline.

Test: adb shell dumpstate
Bug: 274528501
Change-Id: Ic7ee96c6bef60f9c64474669cce4b01e314db905
diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index 47a513b..97ab0b6 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -814,6 +814,8 @@
     printf("Kernel: ");
     DumpFileToFd(STDOUT_FILENO, "", "/proc/version");
     printf("Command line: %s\n", strtok(cmdline_buf, "\n"));
+    printf("Bootconfig: ");
+    DumpFileToFd(STDOUT_FILENO, "", "/proc/bootconfig");
     printf("Uptime: ");
     RunCommandToFd(STDOUT_FILENO, "", {"uptime", "-p"},
                    CommandOptions::WithTimeout(1).Always().Build());