cypress-nvram: remove PROVIDES in NVRAM packages

cypress-nvram: remove PROVIDES in NVRAM packages

PROVIDES for these packages will cause ambiguity and circular dependency
in planned changes.

For example, if there is a package `brcmfmac-firmware-43455-sdio-rpi-cm4`
that depends on `brcmfmac-firmware-43455-sdio-rpi-4b`, there is no way to
tell which one of below packages the system will go for.

 - package named `brcmfmac-firmware-43455-sdio-rpi-4b`
 - package named `cypress-nvram-43455-sdio-rpi-4b` that PROVIDES
   `brcmfmac-firmware-43455-sdio-rpi-4b`

When ambiguity is unacceptable, PROVIDES (aliases) shall be removed and
packages shall only be used through their exact name.

So remove PROVIDES and keep only CONFLICTS.

Signed-off-by: Kuan-Yi Li <kyli@abysm.org>