lib: Add LPDDR5x DRAM type

BUG=none
TEST=Able to build and boot Google, Rex SKU2 (Micron LPDDR5x
MT62F1G32D2DS-026).

Without this code change:
[INFO ]  SPD: module type is UNKNOWN

With this code change:
[INFO ]  SPD: module type is LPDDR5X

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: If620cf51133ca295fd3f1cbecbb472beb337b9fc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69226
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/spd_bin.h

@@ -19,6 +19,7 @@
 #define  SPD_DRAM_LPDDR4X	0x11
 #define  SPD_DRAM_DDR5		0x12
 #define  SPD_DRAM_LPDDR5	0x13
+#define  SPD_DRAM_LPDDR5X	0x15
 #define SPD_DENSITY_BANKS	4
 #define SPD_ADDRESSING		5
 #define SPD_SN_LEN		4