arch: powerpc: add openeuler_defconfig file support for ppc64le compile

 HeXin inclusion
 from HeXin
 commit :NA
 category: feature
 bugzilla: https://gitee.com/openeuler/kernel/issues/I5RYLO?from=project-issueD
 CVE: NA

 -------------------------------------------------

 This is required to support ppc64le.
 key configuration:
      CONFIG_PPC64=y
      CONFIG_PPC_BOOK3S_64=y
      CONFIG_PPC_BOOK3S=y
      CONFIG_PPC64_BOOT_WRAPPER=y
      CONFIG_PPC_WATCHDOG=y
      CONFIG_PPC=y
      CONFIG_PPC_64K_PAGES=y
      CONFIG_PPC_PAGE_SHIFT=16
      CONFIG_PPC_MSI_BITMAP=y
      CONFIG_USB_EHCI_HCD_PPC_OF=y
      CONFIG_USB_OHCI_HCD_PPC_OF_BE=y
      CONFIG_USB_OHCI_HCD_PPC_OF_LE=y
      CONFIG_USB_OHCI_HCD_PPC_OF=y
      CONFIG_PPC_MEM_KEYS=y

 Changes to be committed:
	new file:   arch/powerpc/configs/openeuler_defconfig
Signed-off-by: Nshenghui.qu <shenghui.qu@shingroup.cn>