console: add cputx for integer types when using newlib

Too much existing code assumes using msp430-libc or embtextf; implement
the cprintf part of the integer-to-string capability from embtextf.
bootstrap/clocks: add CFG_LFXT1 make option

Simplify the process of setting boot-time configuration of LFXT1: just
add CFG_LFXT=1 to the make options.
Makefile.common: support override of -mhwmult with msp430-elf

msp430-elf-gcc infers the supported multiplier infrastructure by a
hard-coded list of recognized MCUs embedded in the compiler.  The FR5
class of chips is not part of this list, and with the default selection
it returns zero for all multiply operations.
utility/led: support MCUs that use PxSEL0 but don't have PxSEL1
clock: add BSP430_NOMINAL_MODCLK_HZ

This is a high-frequency low-power clock available from some clock
peripherals and usable in low-power mode when SMCLK is unavailable.
eusci: support FR4 variant that doesn't use ACLK as a source
bootstrap/clocks: support CS4 and refine LED-based diagnostics

Provide feedback that we made it past basic initialization, and expose
the clocks immediately afterward so we can diagnose clock issues before
we have a working console.  Also put in support for the FR4xx variant of
the CS peripheral.
cs4: add peripheral

The FR4xx/2xx family has something it calls a CS (Clock System)
peripheral but it's not the standard FRAM CS or CS_A; its much closer to
a 4xx FLL+.  Support this alternative, using a hack to identify it since
the current TI headers distinctly identify neither this peripheral nor
the 4xx/2xx family.
reindent
exp430fr4133: add platform

Beyond the strangeness of the FR4xx/2xx family, this platform has no
timer that can use ACLK as a capture/compare trigger.
tlv: correct documentation and test validation routine

Change misleading documentation about what the data start value
references.  Test the macro that validates the TLV section, as well as
the underlying algorithm.
periph/adc: add FR4xx/2xx ADC10_B variant support

Kinda ugly but it appears to work.  Note that the voltage setting is not
valid because the FR4133 doesn't support measuring VMID.
exp430fr4133: correct pin map

Was looking at quick-start for FR5969 when filling in BP headers.
rf/cc110x: validate Anaren BP on EXP430FR4133
examples/sensors: add various FRAM-based platforms