flash_fp_mcu: Fix FPMCU flashing on nami/nami-kernelnext
flash_fp_mcu: Fix FPMCU flashing on nami/nami-kernelnext

The 4.4 and 5.4 kernel use different DEVICE constants, but
the kernel version cannot necessarily be inferred from the
platform name. This change adds a regex-based kernel version
check and consolidates config_nami and config_nami-kernelnext
into a single function.

BUG=b:218213808
BRANCH=none
TEST=on bard using both the 4.4 and 5.4 kernels:
     flash_fp_mcu --noservices

Signed-off-by: Matt Davis <f1082e0b0f784dc8e4235f8e7f921d6a18582f08@google.com>
Change-Id: I1c61658d5d652c175fc43dea09d1b40f80ae4cb6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3442758
Reviewed-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec