[PATCH -next] mtd: hyperbus: fix build error about CONFIG_REGMAP

[Mao Wenan]

When CONFIG_MUX_MMIO and CONFIG_HBMC_AM654 are both 'm', there are
some building error as below:

drivers/mux/mmio.c: In function mux_mmio_probe:
drivers/mux/mmio.c:76:20: error: storage size of field isnt known
   struct reg_field field;
                    ^~~~~
drivers/mux/mmio.c:102:15: error: implicit declaration of function devm_regmap_field_alloc; did you mean devm_mux_chip_alloc? [-Werror=implicit-function-declaration]
   fields[i] = devm_regmap_field_alloc(dev, regmap, field);
               ^~~~~~~~~~~~~~~~~~~~~~~
               devm_mux_chip_alloc
drivers/mux/mmio.c:76:20: warning: unused variable field [-Wunused-variable]
   struct reg_field field;
                    ^~~~~
cc1: some warnings being treated as errors
make[2]: *** [drivers/mux/mmio.o] Error 1
make[1]: *** [drivers/mux] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [drivers] Error 2

This because CONFIG_REGMAP is not enable, so change the Kconfig for HBMC_AM654.

Fixes: b07079f1642c("mtd: hyperbus: Add driver for TI's HyperBus memory controller")

Signed-off-by: Mao Wenan <maowenan@xxxxxxxxxx>
---
 drivers/mtd/hyperbus/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/hyperbus/Kconfig b/drivers/mtd/hyperbus/Kconfig
index cff6bbd..f324fa6 100644
--- a/drivers/mtd/hyperbus/Kconfig
+++ b/drivers/mtd/hyperbus/Kconfig
@@ -14,6 +14,8 @@ if MTD_HYPERBUS
 
 config HBMC_AM654
 	tristate "HyperBus controller driver for AM65x SoC"
+	select OF
+	select REGMAP
 	select MULTIPLEXER
 	select MUX_MMIO
 	help
-- 
2.7.4