char: misc: Rename a local variable in misc_init()

Local variable @ret is not used for return value in misc_init().

Give it a different name @misc_proc_file.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250625-fix_mischar-v2-1-25a80f41b090@oss.qualcomm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>