[CORE] vmm_timer: Minor improvement to vmm_timer_timestamp()

The vmm_timer_timestamp() is the most abused API of core. It can be
called even from places where vmm_timer subsystem is not yet initialized
hence this patch adds appropriate sanity check for this function.

Signed-off-by: Anup Patel <anup@brainfault.org>
[DRIVERS] Minor fix in linux/module.h

This patch fixes KBUILD_MODNAME macro which was broken due to
recent changes.

Signed-off-by: Anup Patel <anup@brainfault.org>
[LIBS] Add strspn, strcspn and strtok_r string operations.

Add 3 standard string operation for string manipulation.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[COMMANDS] Add support for execution of a batch/script file.

This patch adds a sub-command to vfs command for running
set of Xvisor commands from a batch/script file. The batch
file is a text file with set of Xvisor commands. The lines
that start with '#' are treated as comment and not executed.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[CORE] vmm_timer: Further improve sanity check in vmm_timer_timestamp()

It can happen that vmm_timer_timestamp() is called after per-cpu
timer control structure is zeroed-out but before per-cpu time counter
is initialized hence we need to ensure that per-cpu timer counter is
initialized before it is used by vmm_timer_timestamp().

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] vmm_clocksource: Improve sanity checks in vmm_timecounter_xxx() APIs

Instead of doing sanity check only for vmm_timer_timestamp() we should
have sanity checks in vmm_timecounter_xxx() APIs to avoid potential
misuse of these APIs hence this patch.

Signed-off-by: Anup Patel <anup@brainfault.org>