fix no output from pipeline when run command hdc file shell bm get -t

Issue:I799HR
Test:libc-test
Signed-off-by: Nrobottoy <wangyaofeng.wang@huawei.com>

musl_src.gni

@@ -2167,7 +2167,6 @@ musl_src_porting_file = [
   "src/stdio/__fdopen.c",
   "src/stdio/vfprintf.c",
   "src/stdio/__stdio_read.c",
-  "src/stdio/__stdio_write.c",
   "src/stdio/fread.c",
   "src/stdio/fmemopen.c",
   "src/stdio/freopen.c",

porting/linux/user/src/internal/stdio_impl.h

@@ -63,7 +63,6 @@ hidden off_t __stdio_seek(FILE *, off_t, int);
 hidden int __stdio_close(FILE *);
 
 hidden int __fill_buffer(FILE *f);
-hidden ssize_t __flush_buffer(FILE *f);
 
 hidden int __toread(FILE *);
 hidden int __towrite(FILE *);

porting/linux/user/src/stdio/__stdio_write.c

-#include "stdio_impl.h"
-#include <sys/uio.h>
-#include <string.h>
-
-ssize_t __flush_buffer(FILE *f)
-{
-	ssize_t cnt = 0;
-	char *wbase = (char *)f->wbase;
-	size_t rem = f->wpos - f->wbase;
-	while (rem > 0) {
-		cnt = syscall(SYS_write, f->fd, wbase, rem);
-		if (cnt < 0) {
-			f->wpos = f->wbase = f->wend = 0;
-			f->flags |= F_ERR;
-			return cnt;
-		}
-		wbase += cnt;
-		rem -= cnt;
-	}
-
-	/* reset file buffer */
-	f->wend = f->buf + f->buf_size;
-	f->wpos = f->wbase = f->buf;
-	return cnt;
-}
-
-size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
-{
-	size_t rem = len;
-	unsigned char *wbuf = (unsigned char *)buf;
-
-	/* flush buffer first */
-	ssize_t cnt = __flush_buffer(f);
-	if (cnt < 0) {
-		return 0;
-	}
-
-	for (;;) {
-		if (f->lbf < 0 && rem <= f->wend - f->wpos) {
-			memcpy(f->wpos, wbuf, rem);
-			f->wpos += rem;
-			return len;
-		}
-
-		/* write directly if
-		 * 1. file buffer < rem
-		 * 2. line buffer mode
-		 */
-		cnt = syscall(SYS_write, f->fd, wbuf, rem);
-		if (cnt < 0) {
-			f->wpos = f->wbase = f->wend = 0;
-			f->flags |= F_ERR;
-			return len - rem;
-		}
-
-		rem -= cnt;
-		wbuf += cnt;
-		if (rem == 0) {
-			break;
-		}
-	}
-
-	return len;
-}