Drop the __efistub_ prefixed exports of various routines that the EFI
stub on LoongArch does not even use.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
 
 #ifdef CONFIG_EFI_STUB
 
-__efistub_memchr               = memchr;
-__efistub_strcat               = strcat;
 __efistub_strcmp               = strcmp;
-__efistub_strncat              = strncat;
-__efistub_strnstr              = strnstr;
-__efistub_strrchr              = strrchr;
 __efistub_kernel_entry         = kernel_entry;
 __efistub_kernel_asize         = kernel_asize;
 __efistub_kernel_fsize         = kernel_fsize;