spi nor sfdp runtime: nph offset

[sandroklarer-pingpong]

Describe the bug
Using the CONFIG_SPI_NOR_SFDP_RUNTIME configuration, by reading out the SFDP, the parameter nph is wrong interpreted.
A value of 0 means 1 parameter headers

So on my flash, where i get a 0 for nph, the flash layouting failed.

code (spi_nor.c) :
const struct jesd216_param_header *phpe = php + MIN(decl_nph, hp->nph);

proposal to fix:
const struct jesd216_param_header *phpe = php + MIN(decl_nph, hp->nph+1);

The JEDEC Standard No. 216 says:
Number of Parameter Headers (NPH)
Specifies the number of parameter headers in the SFDP data structure.
This number is 0-based. Therefore, 0 indicates 1 parameter header.
This number must be revised by a vendor or JEDEC when a new parameter header is
added

To Reproduce
Steps to reproduce the behavior:

1. connect a nor flash like EN25QH64A to your board
2. set up device tree
3. CONFIG_SPI_NOR_SFDP_RUNTIME=y
4. log shows: [00:00:00.003,000] <err> spi_nor: layout setup failed: -134

Expected behavior
Flash setup successful.

[00:00:00.003,000] <inf> spi_nor: PH0: ff00 rev 1.0: 9 DW @ 30
[00:00:00.003,000] <inf> spi_nor: EN25QH64A: 1 MiBy flash

Impact
Useing CONFIG_SPI_NOR_SFDP_MINIMAL

Logs and console output

Environment (please complete the following information):

• OS: Linux
• Toolchain: Zephyr SDK
• zephyr-v2.4.0