drivers/rtc/rtc-mrst.c: use release_mem_region after request_mem_region

The memory allocated using request_mem_region should be released using
release_mem_region, not release_region.

The semantic patch that fixes part of this problem is as follows:
(http://coccinelle.lip6.fr/)

  // <smpl>
  @@
  expression E1,E2,E3;
  @@

  request_mem_region(E1,E2,E3)
  ...
  ?- release_region(E1,E2)
  + release_mem_region(E1,E2)
  // </smpl>

[akpm@linux-foundation.org: use resource_size()]
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>