x86/timers: Move simple_udelay_calibration() past kvmclock_init()

x86/timers: Move simple_udelay_calibration() past kvmclock_init()

simple_udelay_calibration() relies on x86_platform's calibration ops.
For KVM these ops are set late in setup_arch() and so
simple_udelay_calibration() ends up using native version.

Besides being possibly incorrect, this significantly increases kernel
boot time. For example, on my laptop executing start_kernel() by a guest
takes ~10 times more than when KVM's ops are used.

Since early_xdbc_setup_hardware() relies on calibration having been
performed move it too.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: baolu.lu@linux.intel.com
Link: https://lkml.kernel.org/r/20170911185111.20636-1-boris.ostrovsky@oracle.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>