Do not add stack pointer to clobber list

it was being ignored until gcc 9.0 became capable
of flagging this silent ignoring via [1]

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52813<Paste>

Upstream-Status: Submitted [https://chromium-review.googlesource.com/c/linux-syscall-support/+/1390160]
Signed-off-by: Khem Raj <raj.khem@gmail.com>

--- a/src/third_party/lss/linux_syscall_support.h
+++ b/src/third_party/lss/linux_syscall_support.h
@@ -1966,7 +1966,7 @@ struct kernel_statfs {
         __asm__ volatile(LSS_ENTRYPOINT                                       \
                          : "=a" (__res)                                       \
                          : "0" (__NR_##name)                                  \
-                         : "esp", "memory");                                  \
+                         : "memory");                                         \
         LSS_RETURN(type,__res);                                               \
       }
     #undef  _syscall1
@@ -2407,7 +2407,7 @@ struct kernel_statfs {
                                "d"(LSS_SYSCALL_ARG(parent_tidptr)),
                                "r"(LSS_SYSCALL_ARG(newtls)),
                                "r"(LSS_SYSCALL_ARG(child_tidptr))
-                             : "rsp", "memory", "r8", "r10", "r11", "rcx");
+                             : "memory", "r8", "r10", "r11", "rcx");
       }
       LSS_RETURN(int, __res);
     }