pkg/system: remove deprecated MemInfo, ReadMemInfo()

These were deprecated in 2d490800565c410af8564844f52cd9fa34c7b1bf, which
is part of the v24.0.0 release, so we can remove it from master.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/system/meminfo_deprecated.go

@@ -1,16 +0,0 @@
-package system
-
-import "github.com/docker/docker/pkg/meminfo"
-
-// MemInfo contains memory statistics of the host system.
-//
-// Deprecated: use [meminfo.Memory].
-type MemInfo = meminfo.Memory
-
-// ReadMemInfo retrieves memory statistics of the host system and returns a
-// MemInfo type.
-//
-// Deprecated: use [meminfo.Read].
-func ReadMemInfo() (*meminfo.Memory, error) {
-	return meminfo.Read()
-}