include/spi_flash: add RPMC field length defines

The first table from the chapter 4.1 'OP1/OP2 Command Definition: No
Address Phase' of the JEDEC standard JESD260 (Replay Protected Monotonic
Counter (RPMC) for Serial Flash Devices) in the version from April 2021
was used as a reference.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I0050aea6cdc537122bae63fddb417dd9f6b75a02
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84703
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Nicholas Sudsgaard <devel+coreboot@nsudsgaard.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/spi_flash.h

@@ -12,6 +12,10 @@
 #define SPI_OPCODE_WREN 0x06
 #define SPI_OPCODE_FAST_READ 0x0b
 
+/* SPI RPMC field lengths in bytes */
+#define SPI_RPMC_TAG_LEN		12
+#define SPI_RPMC_SIG_LEN		32
+
 struct spi_flash;
 
 /*