PCI: rcar: Avoid defines prefixed with CONFIG

PCI: rcar: Avoid defines prefixed with CONFIG

Defines prefixed with "CONFIG" should be limited to proper Kconfig options,
that are introduced in a Kconfig file.

In the R-car driver the bitmask to configure the SEND_ENABLE mode is named
CONFIG_SEND_ENABLE.

Rename this local definition to a more suitable name, containing the
register bitfield name defined in the R-Car Gen3 rev. 2.30 user
manual.

No functional change.

Link: https://lore.kernel.org/r/20230113084516.31888-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
[lpieralisi@kernel.org: Changed define naming and commit log]
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>