jfs: remove redundant assignments to ipaimap and ipaimap2

The pointers ipaimap and ipaimap2 are re-assigned with values a second
time with the same values when they were initialized. The re-assignments
are redundant and can be removed.

Cleans up two clang scan build warnings:
fs/jfs/jfs_umount.c:42:16: warning: Value stored to 'ipaimap' during
its initialization is never read [deadcode.DeadStores]

fs/jfs/jfs_umount.c:43:16: warning: Value stored to 'ipaimap2' during
its initialization is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>