staging: rtl8723bs: removed function prototypes in core/rtw_efuse.c

fix the following checkpatch issues:

WARNING: externs should be avoided in .c files
35: FILE: drivers/staging/rtl8723bs/core/rtw_efuse.c:35:
+bool

removed two function prototypes in core/rtw_efuse.c and
made definition static

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/e9137945e66eccae8f2ae3eabe720ea648262eca.1616503354.git.fabioaiuto83@gmail.com


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