MdeModulePkg/NvmExpressDxe: Fix wrong logic in GetControllerName()

NvmExpressComponentNameGetControllerName returns EFI_UNSUPPORTED if
child handle is passed. gEfiNvmExpressPassThruProtocolGuid needs to
be passed to EfiTestChildHandle instead of gEfiPciIoProtocolGuid.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Anbazhagan, Baraneedharan" <anbazhagan@hp.com>
Reviewed-by: "Tian, Feng" <feng.tian@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19071 6f19259b-4bc3-4df7-8a09-765794883524