NVMe: Wait for device to acknowledge shutdown
NVMe: Wait for device to acknowledge shutdown

A recent update to the specification makes it clear that the host
is expected to wait for the device to acknowledge the Enable bit
transitioning to 0 as well as waiting for the device to acknowledge a
transition to 1.

Reported-by: Khosrow Panah <8651dd516787b9654aaab5c5724ea52489342e89@idt.com>
Signed-off-by: Matthew Wilcox <ed1245e46949b7b8f2bca25d41520ebc8aeefcf8@intel.com>
Reviewed-by: Keith Busch <695e2a2c1e39535baaa147c5eb4e5da14054d59f@intel.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas