nvmem: core: Check read_only flag for force_ro in bin_attr_nvmem_write()

nvmem: core: Check read_only flag for force_ro in bin_attr_nvmem_write()

The bin_attr_nvmem_write() must check the read_only flag and block
writes on read-only devices, now that a nvmem device can be switched
between read-write and read-only mode at runtime using the force_ro
attribute. Add the missing check.

Fixes: 9d7eb234ac7a ("nvmem: core: Implement force_ro sysfs attribute")
Cc: Stable@vger.kernel.org
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20241030140253.40445-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>