Prefix the Linux KPI's kmem_xxx() functions with linux_ to avoid
conflict with the opensolaris kernel module.

This patch solves a problem where the kernel linker will incorrectly
resolve opensolaris kmem_xxx() functions as linuxkpi ones, which leads
to a panic when these functions are used.

Submitted by: gallatin @
Sponsored by: Mellanox Technologies
MFC after: 1 week