soc/amd/picasso: Disable inclusion of S0i3 firmware by default

Enabling of S0i3 is a mainboard decision. This change sets the option
to include S0i3 firmware by default to 'n'.

BUG=b:154880818

Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: I5d533e317535b01efe9dd32272483296bf4fafab
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40681
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/picasso/Kconfig

@@ -338,6 +338,7 @@ config PSP_LOAD_MP2_FW
 
 config PSP_LOAD_S0I3_FW
 	bool "Include S0I3 blob in PSP build"
+	default n
 	help
 	  Select this item to include the S0i3 file into the PSP build.