linux-user: Make sure initial brk(0) is page-aligned

Fixes: 86f0473 ("linux-user: Fix brk() to release pages")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Message-Id: <mvmpm55qnno.fsf@suse.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit d28b3c9)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

linux-user/syscall.c

@@ -806,7 +806,7 @@ static abi_ulong brk_page;
 
 void target_set_brk(abi_ulong new_brk)
 {
-    target_brk = new_brk;
+    target_brk = TARGET_PAGE_ALIGN(new_brk);
     brk_page = HOST_PAGE_ALIGN(target_brk);
 }