9260 nsmb driver 32-bit ioctl check broken after 8685

Revert changes in usr/src/uts/Makefile.\{targ,uts\}
Let uts/intel/Makefile.intel define \{ALL,DEF\}\_BUILDS for 32-bit only,
Also the platform makefiles: uts/i86pc/Makefile.\* etc.
(Similar to how sparc handled that.)

Add logic to intel/nsmb/Makefile like sparc had to run just the
necessary part of the 32-bit build for the ioctl check.

Ran wsdiff of the proto areas before vs after (no differences).

Checked that we again get a 32-bit ioc_check.h under nsmb/obj32
The ioc_check.h files are not delivered, which is why nobody noticed that this broke after 8685.