lm4: Properly identify TM4 chip used on haswell/baytrail systems
lm4: Properly identify TM4 chip used on haswell/baytrail systems

This chip returns ver/family/partno = 0x10de, as indicated by the
datasheet.  Also switch the identification code to use a switch
statement rather than re-reading the DID1 register in if-then-else.

BUG=chrome-os-partner:23679
BRANCH=none (maybe haswell branches, but it's largely cosmetic)
TEST=version command on rambi identifies the chip as ti tm4e1g31h6zrb B1

Change-Id: I4a3748413de65d3116feb7c444f5a2af5953eecd
Signed-off-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175008
Reviewed-by: Vic Yang <5fd92abeee651458f98e2856f4f200ee971cee4d@chromium.org>

alterapraxisptyltd/chromium-ec,alterapraxisptyltd/chromium-ec,mtk09422/chromiumos-platform-ec,alterapraxisptyltd/chromium-ec,fourier49/BIZ_EC,fourier49/BIZ_EC,coreboot/chrome-ec,thehobn/ec,coreboot/chrome-ec,fourier49/BIZ_EC,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,md5555/ec,fourier49/BZ_DEV_EC,longsleep/ec,gelraen/cros-ec,fourier49/BZ_DEV_EC,eatbyte/chromium-ec,mtk09422/chromiumos-platform-ec,md5555/ec,eatbyte/chromium-ec,longsleep/ec,longsleep/ec,md5555/ec,fourier49/BIZ_EC,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,gelraen/cros-ec,fourier49/BZ_DEV_EC,eatbyte/chromium-ec,akappy7/ChromeOS_EC_LED_Diagnostics,thehobn/ec,longsleep/ec,coreboot/chrome-ec,thehobn/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,alterapraxisptyltd/chromium-ec,thehobn/ec,mtk09422/chromiumos-platform-ec,gelraen/cros-ec,eatbyte/chromium-ec,mtk09422/chromiumos-platform-ec,fourier49/BZ_DEV_EC,gelraen/cros-ec,md5555/ec