sh: KSTK_EIP/KSTK_ESP consistency.

Two of the fields in /proc/[number]/stat are documented in
proc(5) as:

      kstkesp %lu
	     The current value of esp (stack pointer), as
	     found in the kernel stack page for the process.

      kstkeip %lu
	     The current EIP (instruction pointer).

The SH currently prints the the last SP and PC of the process
inside the kernel, while most other archs use the last user
space values.

This patch modifes the SH to display the user space values.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>