lib/vdso: use "grep -E" instead of "egrep"

The latest version of grep claims the egrep is now obsolete so the build
now contains warnings that look like:
	egrep: warning: egrep is obsolescent; using grep -E
fix this up by moving the vdso Makefile to use "grep -E" instead.

Cc: Andy Lutomirski <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: gregkh

lib/vdso/Makefile

@@ -17,6 +17,6 @@ $(error ARCH_REL_TYPE_ABS is not set)
 endif
 
 quiet_cmd_vdso_check = VDSOCHK $@
-      cmd_vdso_check = if $(OBJDUMP) -R $@ | egrep -h "$(ARCH_REL_TYPE_ABS)"; \
+      cmd_vdso_check = if $(OBJDUMP) -R $@ | grep -E -h "$(ARCH_REL_TYPE_ABS)"; \
 		       then (echo >&2 "$@: dynamic relocations are not supported"; \
 			     rm -f $@; /bin/false); fi