clk: boston: Add a driver for MIPS Boston board clocks

Add a driver for the clocks provided by the MIPS Boston board from
Imagination Technologies. 2 clocks are provided - the system clock & the
CPU clock - and each is a simple fixed rate clock whose frequency can be
determined by reading a register provided by the board.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16483/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 36cfea3..251a221 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -219,6 +219,7 @@
 
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
+source "drivers/clk/imgtec/Kconfig"
 source "drivers/clk/mediatek/Kconfig"
 source "drivers/clk/meson/Kconfig"
 source "drivers/clk/mvebu/Kconfig"