[IA64] allow WB /sys/.../legacy_mem mmaps
[IA64] allow WB /sys/.../legacy_mem mmaps

Allow cacheable mmaps of legacy_mem if WB access is supported for the region.
The "legacy_mem" file often contains a shadow option ROM, and some versions of
X depend on this.

Tim Yamin <plasm@roo.me.uk> reported that this change fixes X on a Dell
PowerEdge 3250.

Signed-off-by: Bjorn Helgaas <10beeee9ebfac68af8330145c8378a1d1bb2a283@hp.com>
Signed-off-by: Tony Luck <e7984595ec0368ff920a7b3521dc7093683f6f26@intel.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs