compat: Backport shmem_read_mapping_page()

compat: Backport shmem_read_mapping_page()

This backports:

commit d9d90e5eb70e09903dadff42099b6c948f814050
Author: Hugh Dickins <hughd@google.com>
Date:   Mon Jun 27 16:18:04 2011 -0700

    tmpfs: add shmem_read_mapping_page_gfp

shmem_read_mapping_page() is a wrapper around
shmem_read_mapping_page_gfp().

Trying kernel  3.4.0-030400-generic [OK]
Trying kernel  3.3.7-030307-generic [OK]
Trying kernel  3.2.2-030202-generic [OK]
Trying kernel  3.1.10-030110-generic [OK]
Trying kernel  3.0.18-030018-generic [OK]
Trying kernel  2.6.39-02063904-generic [OK]
Trying kernel  2.6.38-02063808-generic [OK]
Trying kernel  2.6.37-02063706-generic [OK]
Trying kernel  2.6.36-02063604-generic [OK]
Trying kernel  2.6.35-02063512-generic [OK]
Trying kernel  2.6.34-02063410-generic [OK]
Trying kernel  2.6.33-02063305-generic [OK]
Trying kernel  2.6.32-02063255-generic [OK]
Trying kernel  2.6.31-02063113-generic [OK]
Trying kernel  2.6.30-02063010-generic [OK]
Trying kernel  2.6.29-02062906-generic [OK]
Trying kernel  2.6.28-02062810-generic [OK]
Trying kernel  2.6.27-020627-generic [OK]
Trying kernel  2.6.26-020626-generic [OK]
Trying kernel  2.6.25-020625-generic [OK]
Trying kernel  2.6.24-020624-generic [OK]

Signed-off-by: Ozan Çağlayan <ozancag@gmail.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>