arch: Remove clkdev.h asm-generic from Kbuild

Now that every architecture is using the generic clkdev.h file
and we no longer include asm/clkdev.h anywhere in the tree, we
can remove it.

Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: <linux-arch@vger.kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

arch/arc/include/asm/Kbuild

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 generic-y += bugs.h
-generic-y += clkdev.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += emergency-restart.h