samus: change gpio name to ENTERING_RW to match other baords
samus: change gpio name to ENTERING_RW to match other baords

Change the ENTERING_RW gpio name to match other boards so that common/system.c
sets the gpio automatically when jumping to RW.

BUG=none
BRANCH=samus
TEST=make buildall

Change-Id: I8290462a73d99dad0a9f5b8de7ea1c0edb56876e
Signed-off-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/236964
Reviewed-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>

mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,mtk09422/chromiumos-platform-ec,eatbyte/chromium-ec,coreboot/chrome-ec,mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,eatbyte/chromium-ec,coreboot/chrome-ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,akappy7/ChromeOS_EC_LED_Diagnostics,mtk09422/chromiumos-platform-ec,md5555/ec,md5555/ec,coreboot/chrome-ec,eatbyte/chromium-ec,coreboot/chrome-ec,eatbyte/chromium-ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,md5555/ec,md5555/ec,coreboot/chrome-ec,fourier49/BIZ_EC,fourier49/BIZ_EC