samples: bluetooth: peripheral_hr: remove pinmux

Remove pinmux dependency, as it is going to be deprecated.

Signed-off-by: Gerard Marull-Paretas <[email protected]>

Author: gmarull

samples/bluetooth/peripheral_hr/prj_minimal.conf

@@ -12,7 +12,6 @@ CONFIG_BT_DEVICE_APPEARANCE=833
 # Drivers and peripherals
 CONFIG_I2C=n
 CONFIG_WATCHDOG=n
-CONFIG_PINMUX=n
 CONFIG_PINCTRL=n
 CONFIG_SPI=n
 CONFIG_GPIO=n