ARM: mmp: Remove legacy clk code

ARM: mmp: Remove legacy clk code

Remove all the legacy clk code that supports a non-common clk framework
implementation of 'struct clk' in mach-mmp. This code doesn't look to be
compiled anymore given that the MMP is fully supported in the
multi-platform config via ARCH_MULTIPLATFORM as of commit 377524dc4d77
("ARM: mmp: move into ARCH_MULTIPLATFORM"). The ARCH_MULTIPLATFORM
config selects COMMON_CLK and therefore the Makefile rule can never
actually compile the code in these files.

Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Russell King <linux@armlinux.org.uk>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20200409064416.83340-9-sboyd@kernel.org
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
[sboyd@kernel.org: Squash in a clock.h include removal found by Stephen
Rothwell <sfr@canb.auug.org.au>]