kernel: add patch to support en25qh256a

kernel: add patch to support en25qh256a

The EN25QH256A variant of the EN25QH256 doesn't initialize correctly from SFDP
alone and only accesses memory below 8m (addr_width is 4 but read_opcode takes
only 3 bytes).

Set SNOR_F_4B_OPCODES if the flash chip variant was detected using hwcaps.

The fix submitted upstream uses the PARSE_SFDP initializer that is not
available in the kernel used with Openwrt.

Signed-off-by: Leon M. Busch-George <leon@georgemail.eu>