arch: unicore32: kernel: ksyms: remove 'bswapsi2' and 'muldi3' to avoid compiling failure

After check the code, 'bswapsi2' and 'muldi3' are useless for
unicore32, so can remove them to avoid compiling failure.

The related error (with allmodconfig under unicore32):

    LD      init/built-in.o
  arch/unicore32/kernel/built-in.o:(___ksymtab+__muldi3+0x0): undefined reference to `__muldi3'
  arch/unicore32/kernel/built-in.o:(___ksymtab+__bswapsi2+0x0): undefined reference to `__bswapsi2'
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Acked-by: Xuetao Guan <gxt@mprc.pku.edu.cn>
Signed-off-by: Xuetao Guan <gxt@mprc.pku.edu.cn>

arch/unicore32/kernel/ksyms.c

@@ -53,9 +53,7 @@ EXPORT_SYMBOL(__ashrdi3);
 EXPORT_SYMBOL(__divsi3);
 EXPORT_SYMBOL(__lshrdi3);
 EXPORT_SYMBOL(__modsi3);
-EXPORT_SYMBOL(__muldi3);
 EXPORT_SYMBOL(__ucmpdi2);
 EXPORT_SYMBOL(__udivsi3);
 EXPORT_SYMBOL(__umodsi3);
-EXPORT_SYMBOL(__bswapsi2);
 

arch/unicore32/kernel/ksyms.h

@@ -8,8 +8,6 @@ extern void __ashrdi3(void);
 extern void __divsi3(void);
 extern void __lshrdi3(void);
 extern void __modsi3(void);
-extern void __muldi3(void);
 extern void __ucmpdi2(void);
 extern void __udivsi3(void);
 extern void __umodsi3(void);
-extern void __bswapsi2(void);